Thermal conductivity degradation of graphites due to neutron irradiation at low temperature

International Nuclear Information System (INIS)

Snead, L.L.; Burchell, T.D.

1995-01-01

Several graphites and carbon/carbon composites (C/C's) have been irradiated with fission neutrons near 150 C and at fluences up to a displacement level of 0.24 dpa. The unirradiated room temperature thermal conductivity of these materials varied from 114 W/m K for H-451 isotropic graphite, to 670 W/m K for a unidirectional FMI-1D C/C composite. At the irradiation temperature a saturation reduction in thermal conductivity was seen to occur at displacement levels of approximately 0.1 dpa. All materials were seen to degrade to approximately 10 to 14% of their original thermal conductivity after irradiation. The significant recovery of thermal conductivity due to post-irradiation isochronal anneals is also presented. (orig.)

Thermal conductivity of fresh and irradiated U-Mo fuels

Science.gov (United States)

Huber, Tanja K.; Breitkreutz, Harald; Burkes, Douglas E.; Casella, Amanda J.; Casella, Andrew M.; Elgeti, Stefan; Reiter, Christian; Robinson, Adam. B.; Smith, Frances. N.; Wachs, Daniel. M.; Petry, Winfried

2018-05-01

The thermal conductivity of fresh and irradiated U-Mo dispersion and monolithic fuel has been investigated experimentally and compared to theoretical models. During in-pile irradiation, thermal conductivity of fresh dispersion fuel at a temperature of 150 °C decreased from 59 W/m·K to 18 W/m·K at a burn-up of 4.9·1021 f/cc and further to 9 W/m·K at a burn-up of 6.1·1021 f/cc. Fresh monolithic fuel has a considerably lower thermal conductivity of 15 W/m·K at a temperature of 150 °C and consequently its decrease during in-pile irradiation is less steep than for dispersion fuel. For a burn-up of 3.5·1021 f/cc of monolithic fuel, a thermal conductivity of 11 W/m·K at a temperature of 150 °C has been measured by Burkes et al. (2015). The difference of decrease for both fuels originates from effects in the matrix that occur during irradiation, like for dispersion fuel the gradual disappearance of the Al matrix with increased burn-up and the subsequent growth of an interaction layer (IDL) between the U-Mo fuel particle and Al matrix and subsequent matrix hardening. The growth of fission gas bubbles and the decomposition of the U-Mo crystal lattice also affect both dispersion and monolithic fuel.

Mechanical property and conductivity changes in several copper alloys after 13.5 dpa neutron irradiation

International Nuclear Information System (INIS)

Ames, M.; Kohse, G.; Lee, T.S.; Grant, N.J.; Harling, O.K.

1986-01-01

A scoping experiment in which 25 different copper materials of 17 alloy compositions were irradiated to approx.13.5 dpa approx.400 0 C in a fast reactor is described. The materials include rapidly solidified (RS) alloys, with and without oxide dispersion strengthening, as well as conventionally processed alloys. Immersion density (swelling), electrical conductivity (which can be related to thermal conductivity), and yield stress and ductility by miniature disk bend testing have been measured before and after irradiation. It was found, in general, that the Rs alloys are stable under irradiation to 13.5 dpa, showing small conductivity changes and little or no swelling. Reduction of strength and ductility, in post-irradiation tests at the irradiation temperature, are not generally observed. Some conventionally processed alloys also performed well, although irradiation softening and swelling of several percent were observed in some cases, and pure copper swelled in excess of 5%. It is concluded that a number of copper alloys should receive further study, and that higher dose irradiations will be required to establish the limits of swelling suppression in these alloys

Enhancement of ionic conductivity in stabilized zirconia ceramics under millimeter-wave irradiation heating

International Nuclear Information System (INIS)

Kishimoto, Akira; Ayano, Keiko; Hayashi, Hidetaka

2011-01-01

Ionic conductivity in yttria-stabilized zirconia ceramics under millimeter-wave irradiation heating was compared with that obtained using conventional heating. The former was found to result in higher conductivity than the latter. Enhancement of the ionic conductivity and the reduction in activation energy seemed to depend on self-heating resulting from the millimeter-wave irradiation. Millimeter-wave irradiation heating restricted the degradation in conductivity accompanying over-substitution, suggesting the optimum structure that provided the maximum conductivity could be different between the two heating methods.

Dielectric relaxation and ac conduction in γ-irradiated UHMWPE/MWCNTs nano composites: Impedance spectroscopy analysis

International Nuclear Information System (INIS)

Maqbool, Syed Asad; Mehmood, Malik Sajjad; Mukhtar, Saqlain Saqib; Baluch, Mansoor A.; Khan, Shamim; Yasin, Tariq; Khan, Yaqoob

2017-01-01

The dielectric behavior of γ-irradiated ultra-high molecular weight polyethylene (UHMWPE) and its nano composites (NCs) with γ-ray modified multi wall carbon nano tubes (γ-MWCNTs) and MWCNTs had been studied using impedance spectroscopy. The study had been carried out in the frequency range of 20–2 MHz at room temperature. All samples (pure and NCs) were prepared in the form of sheets and irradiated with γ-dose of 50 kGy and 100 kGy, respectively. The comprehensive analysis of results revealed that resistivity of UHMWPE for conduction decreased on irradiation and incorporation of MWCNTs (whether γ ray modified or un-modified) due to the radiation induced damage and conductive networks induced by MWCNTs. At low frequency range a significant increase in the dielectric constant had been observed because of irradiation and addition of MWNCTs. The trend of loss tangent and ac conductivity for each investigated sample depended on resistivity offered and had a decreasing trend as a function of frequency. Moreover, dissipation factor increased with the incorporation of MWNCTs and irradiation from 0.12 to 0.22. In addition to this, non-frequency dependent static dielectric constant was also found to increase with irradiation and incorporation of MWCNTs. The relaxation time was found to increase from 1.2 to 4.3 ms due to hindrance offered by radiation induced mutual cross linking of PE chains and polymer-MWNCTs bindings. - Highlights: • The resistivity for conduction in pristine UHMWPE is decreased with γ-irradiation. • Conduction in PE/MWCNTs nanocomposites increased due to MWCNTs addition. • Static dielectric constant of UHMWPE increased with γ-irradiation. • Static dielectric constant of UHMWPE increased due to MWCNTs incorporation.

A review of the studies on the wholesomeness of irradiated wheat, conducted at the National Institute of Nutrition, India

International Nuclear Information System (INIS)

Vijayalaxmi; Srikantia, S.G.; Mysore Univ. Coll.

1989-01-01

The wholesomeness of irradiated wheat was investigated in a series of experiments involving several species of animals and a small number of children, at the National Institute of Nutrition in India. Our observations indicated some effects following the feeding of freshly irradiated wheat while no such changes were found in the groups fed either unirradiated or stored irradiated wheat. Also, there were no significant differences between the groups fed unirradiated and stored irradiated wheat. Based on these results, a recommendation had been made to the government that when subjected to irradiation, wheat should be stored for at least 3 months before considering it as safe for human consumption. Similar experiments conducted in an establishment of the Department of Atomic Energy in India indicated no undesirable effects, unlike those found in our studies, and this had led to the development of a serious controversy. In this paper, we have not only reviewed our studies in the light of subsequent research independently carried out in other laboratories but also have tried to answer some of the criticisms made against our studies, so that some of the misunderstandings of our work are seen in proper perspective. (author)

Investigation of Irradiation Effects on Conducting Composite of Polypyrole/Bentonite

Directory of Open Access Journals (Sweden)

Orhan Karabulut

2012-12-01

Full Text Available Abstract: In the present study, polypyrrole/bentonite (PPy/Bnt composite was synthesized into the Bnt interlayers by chemical oxidation polymerization. The irradiation process was carried out in air in a conventional gamma chamber, which uses a 60Co source, and the composite was exposed to a dose of 40 kGy. Effects of irradiation on the composite were investigated by means of FTIR, UV-visible absorption, TGA, XRD, SEM and temperature dependent electrical conductivity in the temperature range of 290-410 K. The initial decomposition temperature of pristine PPy/Bnt composite was found higher than irradiated PPy/Bnt composite. The XRD patterns revealed that the intensity of the peaks changed with irradiation. It was found from temperature dependent conductivity measurements that the radiation significantly influenced the conductivity of PPy/Bnt composite. The conductivity results show that dominant conduction mechanisms were hopping for both PPy/Bnt composite and irradiated samples due to wide range of localized states present near the Fermi level. Key words: Polypyrrole, bentonite, conducting composite, gamma irradiation. Polipirol/Bentonit İletken Kompozitine Radyasyon Etkilerinin Araştırılması Özet: Bu çalışmada, polipirol/bentonit (PPy/Bnt kompoziti, Bnt tabakaları arasında kimyasal oksidasyon polimerizasyonu yoluyla sentezlendi. Radyasyon uygulaması 60Co kaynağının kullanıldığı bir gama çemberi içerisinde hava ortamında gerçekleştirildi ve kompozite 40 kGy doz uygulandı. Kompozite radyasyon etkileri, FTIR, UV, TGA, XRD, SEM ve 290-410 K sıcaklık aralığında sıcaklığa bağlı elektriksel iletkenlik ölçümleri ile incelendi. Saf PPy/Bnt kompozitinin başlangıç bozunma sıcaklığı radyasyona uğramış PPy/Bnt kompozitinden daha yüksek olduğu bulundu. XRD desenlerine ait pik yoğunluğunun radyasyon ile değiştiği görüldü. Sıcaklığa bağlı iletkenlik ölçümlerinden radyasyonlanma sonucunda, PPy

Enhancement of conductivity in polyaniline-[poly(vinylidene chloride)-co-(vinyl acetate)] blends by irradiation

International Nuclear Information System (INIS)

Bodugoez-Sentuerk, Hatice; Gueven, Olgun

2011-01-01

In this study we have prepared conductive poly(aniline), (PANI) blends with poly(vinylidene chloride-co-vinyl acetate), [P(VDC-co-VAc)] copolymer with varying compositions using gamma radiation to induce conductivity. A number of blends with different compositions were prepared by solution casting followed by irradiation in a 60 Co gamma cell to different doses up to 800 kGy. Electrical conductivity of the blends was measured before and after irradiation using a four-probe technique. Increasing radiation dose resulted in an increase of 9 orders of magnitude in the conductivity of P(VDC-co-VAc)/(PANI) films reaching 0.1 S/cm at 500 kGy and beyond this dose a decrease was observed. Effect of film thickness on conductivity of the blends was investigated and a slight increase of an order of magnitude was observed on increasing the film thickness from 50 to 200 μm. It was also observed that PANI blends exhibited a stretch dependent small increase in conductivity. The conductivity of the irradiated films was found to be stable for up to 12 months under ambient conditions.

Study of defect annealing behaviour in neutron irradiated Cu and Fe using positron annihilation and electrical conductivity

International Nuclear Information System (INIS)

Eldrup, M.; Singh, B.N.

2000-01-01

To compare the defect accumulation and the annealing behaviour in an fcc and a bcc metal, OFHC-Cu and pure Fe were neutron irradiated at 100 deg. C to a fluence of 1.5 x 10 24 n/m 2 , (E > 1 MeV). Isochronal annealing was carried out and the annealing behaviour followed by positron annihilation spectroscopy (PAS) as well as electrical conductivity measurements. The results for the two specimens in the as-irradiated state are very different. In Cu the defect positron lifetime is characteristic of single vacancies, very small vacancy clusters or stacking fault tetrahedra, while in Fe the defect lifetimes confirm the presence of micro-voids and voids. The electrical conductivity, on the other hand does not discriminate between the two types of damage in the irradiated specimens. During annealing of the irradiated Fe below stage V, the average void size grows by migration and coalescence of the micro-voids and voids. At and above stage V the void density decreases and the voids finally anneal out at ∼500 deg. C. In contrast, the annealing of irradiated Cu below stage V does not yield any evidence for the evolution of micro-voids or voids. The implications of these results are discussed. One conclusion is that neutron irradiation below stage V causes higher void swelling in bcc iron than in fcc copper

Conductive stability of graphene on PET and glass substrates under blue light irradiation

Science.gov (United States)

Cao, Xueying; Liu, Xianming; Li, Xiangdi; Lei, Xiaohua; Chen, Weimin

2018-01-01

Electrical properties of graphene transparent conductive film under visible light irradiation are investigated. The CVD-grown graphene on Polyethylene Terephthalate (PET) and glass substrates for flexible and rigid touch screen display application are chosen for research. The resistances of graphene with and without gold trichloride (AuCl3) doping are measured in vacuum and atmosphere environment under blue light irradiation. Results show that the conductivities of all samples change slowly under light irradiation. The change rate and degree are related to the substrate material, doping, environment and lighting power. Graphene on flexible PET substrate is more stable than that on rigid glass substrate. Doping can improve the electrical conductivity but induce instability under light irradiation. Finally, the main reason resulting in the graphene resistance slowly increasing under blue light irradiation is analyzed.

Enhanced electrical conductivity in Xe ion irradiated CNT based transparent conducting electrode on PET substrate

Science.gov (United States)

Surbhi; Sharma, Vikas; Singh, Satyavir; Garg, Priyanka; Asokan, K.; Sachdev, Kanupriya

2018-02-01

An investigation of MWCNT-based hybrid electrode films with improved electrical conductivity after Xe ion irradiation is reported. A multilayer hybrid structure of Ag-MWCNT layer embedded in between two ZnO layers was fabricated and evaluated, pre and post 100 keV Xe ion irradiation, for their performance as Transparent Conducting Electrode in terms of their optical and electrical properties. X-ray diffraction pattern exhibits highly c-axis oriented ZnO films with a small variation in lattice parameters with an increase in ion fluence. There is no significant change in the surface roughness of these films. Raman spectra were used to confirm the presence of CNT. The pristine multilayer films exhibit an average transmittance of ˜70% in the entire visible region and the transmittance increases with Xe ion fluence. A significant enhancement in electrical conductivity post-Xe ion irradiation viz from 1.14 × 10-7 Ω-1 cm-1 (pristine) to 7.04 × 103 Ω-1 cm-1 is seen which is due to the high connectivity in the top layer with Ag-CNT hybrid layer facilitating the smooth transfer of electrons.

Development of an apparatus for measuring the thermal conductivity of irradiated or non-irradiated graphite; Realisation d'un appareil de mesure de la conductibilite thermique du graphite irradie ou non irradie

Energy Technology Data Exchange (ETDEWEB)

Bocquet, M; Micaud, G

1962-07-01

An apparatus was developed for measuring the thermal conductivity coefficient K of irradiated or non-irradiated graphite. The measurement of K at around room temperature with an accuracy of about 6% is possible. The study specimen is placed in a vacuum between a hot and a cold source which create a temperature gradient {delta}{theta}/ {delta}x in the steady state. The amount of heat transferred, Q, is deduced from the electrical power dissipated at the hot source, after allowing for heat losses. The thermal conductivity coefficient is defined as: K = Q/S. {delta}x/{delta}{theta}, S being the cross section of the sample. Systematic studies have made it possible to determine the mean values of the thermal conductivity. (authors) [French] Un appareil de mesure du coefficient de conductibilite thermique K du graphite irradie ou non irradie a ete realise. Utilisant le principe du transfert de chaleur, il permet de mesurer K au voisinage de la temperature ambiante avec une precision de 6 pour cent environ. L'echantillon de graphite etudie est place sous vide entre une source chaude et une source froide qui creent en regime permanent un gradient de temperature {delta}{theta}/{delta}x La quantite de chaleur transferee Q est deduite de la puissance electrique dissipee dans la source chaude en deduisant les pertes thermiques. Le coefficient de conductibilite thermique est defini par: K = Q/S. {delta}x/{delta}{theta} S designant la section de l'echantillon. Des etudes systematiques ont permis de determiner pour differents graphites non irradies les valeurs moyennes des coefficients de conductibilite thermique. Ces etudes ont mis en evidence pour un type de graphite donne, l'influence de la densite apparente sur le coefficient de conductibilite thermique. A partir de mesures effectuees sur des echantillons de graphite irradies preleves par carottage dans les empilements des reacteurs a moderateur de graphite les variations du rapport K0/Ki en fonction de la dose et de la

Measurement of DC electrical conductivity of alumina during spallation-neutron irradiation

International Nuclear Information System (INIS)

Farnum, E.H.; Clinard, F.W. Jr.; Kennedy, J.C. III; Sommer, W.F.; Dammeyer, M.D.

1993-01-01

An irradiation experiment was carried out during the summer of 1992 at the Los Alamos Spallation Radiation Effects Facility (LASREF). In situ measurements of electrical conductivity in alumina, sapphire and mineral-insulated electrical cables were made at 640 degrees C, 590 degrees C and 400 degrees C. Both DC and AC (100 Hz to 1 MHz) measurements were made to fluence of approximately 3 x 10 23 n/m 2 . Optical absorption from 200 nm to 800 nm was measured in pure silica - and OH-doped silica-core optical fibers during the irradiation. A large number of passive samples were included in the irradiation, some at the furnace temperatures and some at ambient temperature. This report describes preliminary analysis of the DC conductivity measurements. The AC measurements are analyzed in the companion report. All samples are being recovered for post-irradiation examination as this report is being written in May, 1993. Final analysis of the conductivity data awaits the results of measured fluence from activation foils and will be published at ICFRM-6

Heavy ions amorphous semiconductors irradiation study

International Nuclear Information System (INIS)

Benmalek, M.

1978-01-01

The behavior of amorphous semiconductors (germanium and germanium and arsenic tellurides) under ion bombardment at energies up to 2 MeV was studied. The irradiation induced modifications were followed using electrical parameter changes (resistivity and activation energy) and by means of the transmission electron microscopy observations. The electrical conductivity enhancement of the irradiated samples was interpreted using the late conduction theories in amorphous compounds. In amorphous germanium, Electron Microscopy showed the formations of 'globules', these defects are similar to voids observed in irradiated metals. The displacement cascade theory was used for the interpretation of the irradiation induced defects formation and a coalescence mechanism of growth was pointed out for the vacancy agglomeration [fr

Study of the effect of neutron and electron irradiations on the low temperature thermal conductivity of germanium and silicon

International Nuclear Information System (INIS)

Vandevyver, M.

1967-06-01

The main results obtained from this work are the following: 1 Neutron irradiation (at 300 deg. K) produces lattice defects in germanium and silicon, and a corresponding very large lowering of the thermal conductivity is observed in the low temperature region (4-300 ). The results obtained have been explained with the help of the following hypotheses: for silicon a scattering of phonons by the stress fields produced by the defects; for germanium, a supplementary scattering of the electron phonon type. 2 Annealing treatments carried out on these materials above 373 deg. K restored the thermal conductivity over the whole temperature range of the measurements (4-300 deg. K); in the case of both germanium and silicon there were two steps in the annealing process. 3 A study of the thermal conductivity of germanium (initially P or N) after an electronic irradiation showed that the scattering of phonons could depend on the state of charge of the defects thus produced. (author) [fr

Study of the conductivity induced by radiation in teflon irradiated by X-ray

International Nuclear Information System (INIS)

Faria, R.M.

1980-01-01

It's measured the X-ray induced currents in teflon FEP which show the following features: a) At the beginning the current increases and reaches a maximum at about 10s, b) It decays slowly during 30 minutes, when a steady state is reached the delayed conductivity was also measured. The sample were 25 μm thick and the irradiated area was 12,5 cm 2 ; the applied field was of the order of 10 4 V/cm and the dose rate of order of 10 2 R/S. It was observed that a new measurement of the induced conductivity does not duplicate the first one, but after a few hours it comes back to the original one. In order to show that the increase and the decrease of the current is not caused by an electric field effect we realized a measurement where we polled the sample intermitently while it was irradiated. The current thus obtained had about the same values of the first measurement, when the voltage was applied all the time during the measurement. The absorption current of a teflon sample which shows after some days the effect of its variation due the variation of the ambiental temperature are measured. (Author) [pt

In-pile measurement of the thermal conductivity of irradiated metallic fuel

International Nuclear Information System (INIS)

Bauer, T.H.; Holland, J.W.

1995-01-01

Transient test data and posttest measurements from recent in-pile overpower transient experiments are used for an in situ determination of metallic fuel thermal conductivity. For test pins that undergo melting but remain intact, a technique is described that relates fuel thermal conductivity to peak pin power during the transient and a posttest measured melt radius. Conductivity estimates and their uncertainty are made for a database of four irradiated Integral Fast Reactor-type metal fuel pins of relatively low burnup (<3 at.%). In the assessment of results, averages and trends of measured fuel thermal conductivity are correlated to local burnup. Emphasis is placed on the changes of conductivity that take place with burnup-induced swelling and sodium logging. Measurements are used to validate simple empirically based analytical models that describe thermal conductivity of porous media and that are recommended for general thermal analyses of irradiated metallic fuel

Analysis of neutron irradiation effects on thermal conductivity of SiC-based composites and monolithic ceramics

Energy Technology Data Exchange (ETDEWEB)

Youngblood, G.E.; Senor, D.J. [Pacific Northwest National Lab., Richland, WA (United States)

1997-08-01

After irradiation of a variety of SiC-based materials to 33 or 43 dpa-SiC at 1000{degrees}C, their thermal conductivity values were degraded and became relatively temperature independent, which indicates that the thermal resistivity was dominated by point defect scattering. The magnitude of irradiation-induced conductivity degradation was greater at lower temperatures and typically was larger for materials with higher unirradiated conductivity. From these data, a K{sub irr}/K{sub unirr} ratio map which predicts the expected equilibrium thermal conductivity for most SiC-based materials as a function of irradiation temperature was derived. Due to a short-term EOC irradiation at 575{degrees} {+-} 60{degrees}C, a duplex irradiation defect structure was established. Based on an analysis of the conductivity and swelling recovery after post-irradiation anneals for these materials with the duplex defect structure, several consequences for irradiating SiC at temperatures of 1000{degrees}C or above are given. In particular, the thermal conductivity degradation in the fusion relevant 800{degrees}-1000{degrees}C temperature range may be more severe than inferred from SiC swelling behavior.

Analysis of neutron irradiation effects on thermal conductivity of SiC-based composites and monolithic ceramics

International Nuclear Information System (INIS)

Youngblood, G.E.; Senor, D.J.

1997-01-01

After irradiation of a variety of SiC-based materials to 33 or 43 dpa-SiC at 1000 degrees C, their thermal conductivity values were degraded and became relatively temperature independent, which indicates that the thermal resistivity was dominated by point defect scattering. The magnitude of irradiation-induced conductivity degradation was greater at lower temperatures and typically was larger for materials with higher unirradiated conductivity. From these data, a K irr /K unirr ratio map which predicts the expected equilibrium thermal conductivity for most SiC-based materials as a function of irradiation temperature was derived. Due to a short-term EOC irradiation at 575 degrees ± 60 degrees C, a duplex irradiation defect structure was established. Based on an analysis of the conductivity and swelling recovery after post-irradiation anneals for these materials with the duplex defect structure, several consequences for irradiating SiC at temperatures of 1000 degrees C or above are given. In particular, the thermal conductivity degradation in the fusion relevant 800 degrees-1000 degrees C temperature range may be more severe than inferred from SiC swelling behavior

Tuning the conductivity of vanadium dioxide films on silicon by swift heavy ion irradiation

Directory of Open Access Journals (Sweden)

H. Hofsäss

2011-09-01

Full Text Available We demonstrate the generation of a persistent conductivity increase in vanadium dioxide thin films grown on single crystal silicon by irradiation with 1 GeV 238U swift heavy ions at room temperature. VO2 undergoes a temperature driven metal-insulator-transition (MIT at 67 °C. After room temperature ion irradiation with high electronic energy loss of 50 keV/nm the conductivity of the films below the transition temperature is strongly increased proportional to the ion fluence of 5·109 U/cm2 and 1·1010 U/cm2. At high temperatures the conductivity decreases slightly. The ion irradiation slightly reduces the MIT temperature. This observed conductivity change is persistent and remains after heating the samples above the transition temperature and subsequent cooling. Low temperature measurements down to 15 K show no further MIT below room temperature. Although the conductivity increase after irradiation at such low fluences is due to single ion track effects, atomic force microscopy (AFM measurements do not show surface hillocks, which are characteristic for ion tracks in other materials. Conductive AFM gives no evidence for conducting ion tracks but rather suggests the existence of conducting regions around poorly conducting ion tracks, possible due to stress generation. Another explanation of the persistent conductivity change could be the ion-induced modification of a high resistivity interface layer formed during film growth between the vanadium dioxide film and the n-Silicon substrate. The swift heavy ions may generate conducting filaments through this layer, thus increasing the effective contact area. Swift heavy ion irradiation can thus be used to tune the conductivity of VO2 films on silicon substrates.

Structural and electrical evolution of He ion irradiated hydrocarbon films observed by conductive atomic force microscopy

International Nuclear Information System (INIS)

Fan, Hongyu; Yang, Deming; Sun, Li; Yang, Qi; Niu, Jinhai; Bi, Zhenhua; Liu, Dongping

2013-01-01

Polymer-like hydrocarbon films are irradiated with 100 keV He ion at the fluences of 1.0 × 10 15 –1.0 × 10 17 ions/cm 2 or at the irradiation temperature ranging from 25 to 600 °C. Conductive atomic force microscopy (CAFM) has been used to evaluate the nanoscale electron conducting properties of these irradiated hydrocarbon films. Nanoscale and conducting defects have been formed in the hydrocarbon films irradiated at a relatively high ion fluence (1.0 × 10 17 ions/cm 2 ) or an elevated sample temperature. Analysis indicates that He ion irradiation results in the evolution of polymer-like hydrocarbon into a dense structure containing a large fraction of sp 2 carbon clusters. The sp 2 carbon clusters formed in irradiated hydrocarbon films can contribute to the formation of filament-like conducting channels with a relatively high local field-enhancing factor. Measurements indicate that the growth of nanoscale defects due to He ion irradiation can result in the surface swelling of irradiated hydrocarbon films at a relatively high ion fluences or elevated temperature

Hopping conduction in gamma-irradiated InSe and InSe:Sn single crystals

International Nuclear Information System (INIS)

MUSTAFAEVA, S.N.; ISMAILOV, A.A.; ASADOV, M.M.

2010-01-01

Full text : The semiconductive InSe layer compound is characterized by a strong covalent bond inside the layers and a weak Van der Waals bonding between them. It was shown that across the layers of InSe single crystals at low temperatures (T ≤ 200 K) at direct current (dc) hopping conduction through localized states near the Fermi level takes place. The results of dc-conductivity of gamma-irradiated p-InSe and n-InSe : Sn layer single crystals have been presented in this work. ρ-InSe single crystal specimens grown by the Bridgman method were used in the experiments. Plates of the crystals under study were obtained by cleaving along the layers of single crystal ingots. The single-crystal InSe samples for electric measurements had the form of planar capacitors normal to the C axis of the crystals, with silver-paste electrodes. The thickness of the InSe samples was 300 mkm. Co 60 serves as the source of irradiation with energy of gamma-quantum equal to 1.3 MeV. The electric properties of non-irradiated and gamma-irradiated InSe crystals were measured under the same conditions. It is revealed that InSe and InSe : Sn (0.2 and 0.4 mole percent Sn) single crystals exhibit a variable range hopping conduction along a normal to their natural layers at temperatures T≤200 K in a dc electric field. From experimental data the parameters of localized states of p-InSe and n-InSe : Sn were calculated before and after gamma-irradiation. It is revealed that gamma-irradiation of p-InSe and n-InSe : Sn (0.2 and 0.4 mole percent Sn) single crystals leads to significant change of localized states parameters. After gamma-irradiation the density of states near the Fermi level increased, but their energy spread and the average jump distance decreased. The concentrations of radiated defects were estimated in p-InSe (5.18*10 1 7 sm - 3) and n-InSe : Sn (2.5*10 1 7 - 2.7*10 1 8 sm - 3) single crystals. The present results demonstrate that gamma-irradiation offers the possibility of tuning

Effect of swift heavy ion (SHI) irradiation on transparent conducting oxide electrodes for dye-sensitized solar cell applications

International Nuclear Information System (INIS)

Singh, Hemant Kr.; Avasthi, D.K.; Aggarwal, Shruti

2015-01-01

Highlights: •The objective is to study the effect of swift heavy ion (SHI) irradiation on photoanode of DSSC for better efficiency. •This work presents the effect of SHI irradiation on various Transparent conducting oxides (TCOs). •Effects are studied in terms of conductivity and transmittance of TCOs. •ITO-PET gives best results in comparison to ITO and FTO for DSSC application under SHI irradiation. -- Abstract: Transparent conducting oxides (TCOs) are used as electrodes in dye-sensitized solar cells (DSSCs) because of their properties such as high transmittance and low resistivity. In the present work, the effects of swift heavy ion (SHI) irradiation on various types of TCOs are presented. The objective of this study is to investigate the effect of SHI on TCOs. For the present study, three different types of TCOs are considered, namely, (a) FTO (fluorine-doped tin oxide, SnO 2 :F) on a Nippon glass substrate, (b) ITO (indium tin oxide, In 2 O 3 :Sn) coated on polyethylene terephthalate (PET) on a Corning glass substrate, and (c) ITO on a Corning glass substrate. These films are irradiated with 120 MeV Ag +9 ions at fluences ranging from 3.0 × 10 11 ions/cm 2 to 3.0 × 10 13 ions/cm 2 . The structural, morphological, optical and electrical properties are studied via X-ray diffraction (XRD), atomic force microscopy (AFM), UV–Vis absorption spectroscopy and four-probe resistivity measurements, respectively. The ITO-PET electrode is found to exhibit superior conductivity and transmittance properties in comparison with the others after irradiation and, therefore, to be the most suitable for solar cell applications

Conductivity enhancement in SiO2 doped PVA:PVDF nanocomposite polymer electrolyte by gamma ray irradiation

Science.gov (United States)

Hema, M.; Tamilselvi, P.; Pandaram, P.

2017-07-01

Nanocomposite polymer electrolyte has been irradiated with 15 Gy Gamma rays. Exposure of gamma radiation caused scissoring and crosslinking of polymer chains thereby increasing amorphous phase of the polymer matrix because of which the ionic conductivity has been enhanced. Ionic conductivity of irradiated nanocomposite polymer electrolyte is enhanced to 9.4 × 10-4 Scm-1 at 303 K compared to un-irradiated system (σ ∼ 1.7 × 10-4 Scm-1). Temperature dependence of ionic conductivity of both un-irradiated and irradiated systems obeys VTF relation. Frequency and temperature dependence of dielectric and modulus of both systems have been analyzed. The ionic transference number of polymer electrolyte has been calculated by Wagner's polarization technique and it confirms that conducting species are predominantly due to ions in both systems.

Structural and electrical evolution of He ion irradiated hydrocarbon films observed by conductive atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Fan, Hongyu [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China); Yang, Deming [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China); School of Science, Changchun University of Science and Technology, Changchun, Jilin 130022 (China); Sun, Li [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China); School of Physics, Liaoning Normal University, Dalian 116023 (China); Yang, Qi; Niu, Jinhai; Bi, Zhenhua [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China); Liu, Dongping, E-mail: dongping.liu@dlnu.edu.cn [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China); Fujian Key Laboratory for Plasma and Magnetic Resonance, Department of Electronic Science, Aeronautics, School of Physics and Mechanical and Electrical Engineering, Xiamen University, Xiamen, Fujian 361005 (China)

2013-10-01

Polymer-like hydrocarbon films are irradiated with 100 keV He ion at the fluences of 1.0 × 10{sup 15}–1.0 × 10{sup 17} ions/cm{sup 2} or at the irradiation temperature ranging from 25 to 600 °C. Conductive atomic force microscopy (CAFM) has been used to evaluate the nanoscale electron conducting properties of these irradiated hydrocarbon films. Nanoscale and conducting defects have been formed in the hydrocarbon films irradiated at a relatively high ion fluence (1.0 × 10{sup 17} ions/cm{sup 2}) or an elevated sample temperature. Analysis indicates that He ion irradiation results in the evolution of polymer-like hydrocarbon into a dense structure containing a large fraction of sp{sup 2} carbon clusters. The sp{sup 2} carbon clusters formed in irradiated hydrocarbon films can contribute to the formation of filament-like conducting channels with a relatively high local field-enhancing factor. Measurements indicate that the growth of nanoscale defects due to He ion irradiation can result in the surface swelling of irradiated hydrocarbon films at a relatively high ion fluences or elevated temperature.

Fuel Performance Modeling of U-Mo Dispersion Fuel: The thermal conductivity of the interaction layers of the irradiated U-Mo dispersion fuel

Energy Technology Data Exchange (ETDEWEB)

Mistarhi, Qusai M.; Ryu, Ho Jin [KAIST, Daejeon (Korea, Republic of)

2016-05-15

U-Mo/Al dispersion fuel performed well at a low burn-up. However, higher burn-up and higher fission rate irradiation testing showed enhanced fuel meat swelling which was caused by high interaction layer growth and pore formation. The performance of the dispersion type fuel in the irradiation and un-irradiation environment is very important. During the fabrication of the dispersion type fuel an Interaction Layer (IL) is formed due to the inter-diffusion between the U-Mo fuel particles and the Al matrix which is an intermetallic compound (U,Mo)Alx. During irradiation, the IL becomes amorphous causing a further decrease in the thermal conductivity and an increase in the centerline temperature of the fuel meat. Several analytical models and numerical methods were developed to study the performance of the unirradiated U-Mo/Al dispersion fuel. Two analytical models were developed to study the performance of the irradiated U-Mo/Al dispersion fuel. In these models, the thermal conductivity of the IL was assumed to be constant. The properties of the irradiated U-Mo dispersion fuel have been investigated recently by Huber et al. The objective of this study is to develop a correlation for IL thermal conductivity during irradiation as a function of the temperature and fission density from the experimentally measured thermal conductivity of the irradiated U-Mo/Al dispersion fuel. The thermal conductivity of IL during irradiation was calculated from the experimentally measured data and a correlation was developed from the thermal conductivity of IL as a function of T and fission density.

Effect of thermal gab conductance for MoO3 ampoules irradiated in a high neutron flux

International Nuclear Information System (INIS)

Abdelhady, Amr

2010-01-01

During the irradiation process of MoO 3 powder with in a high neutron flux, energy deposited in the powder must be released to avoid energy accumulation. The temperature increasing in the powder due to energy accumulation may cause powder phase change and under certain conditions the temperature may reach the melting point. An analytical model was developed to study the effect of gap conductance on the temperature distribution in the powder during the irradiation process. The gap conductance model was studied for helium and nitrogen gases at different pressures to obtain the optimum conditions verifying the safety in heat transfer point of view. It was found that the gap conductance is a function of gas pressure. The model provided the optimum conductivity for the gap filled with helium gas at 1 atm pressure. (orig.)

Effect of swift heavy ion (SHI) irradiation on transparent conducting oxide electrodes for dye-sensitized solar cell applications

Energy Technology Data Exchange (ETDEWEB)

Singh, Hemant Kr. [University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, New Delhi (India); Avasthi, D.K. [Inter University Accelerator Center, Post Box 10502, New Delhi (India); Aggarwal, Shruti, E-mail: shruti.al@gmail.com [University School of Basic and Applied Sciences, Guru Gobind Singh Indraprastha University, New Delhi (India)

2015-06-15

Highlights: •The objective is to study the effect of swift heavy ion (SHI) irradiation on photoanode of DSSC for better efficiency. •This work presents the effect of SHI irradiation on various Transparent conducting oxides (TCOs). •Effects are studied in terms of conductivity and transmittance of TCOs. •ITO-PET gives best results in comparison to ITO and FTO for DSSC application under SHI irradiation. -- Abstract: Transparent conducting oxides (TCOs) are used as electrodes in dye-sensitized solar cells (DSSCs) because of their properties such as high transmittance and low resistivity. In the present work, the effects of swift heavy ion (SHI) irradiation on various types of TCOs are presented. The objective of this study is to investigate the effect of SHI on TCOs. For the present study, three different types of TCOs are considered, namely, (a) FTO (fluorine-doped tin oxide, SnO{sub 2}:F) on a Nippon glass substrate, (b) ITO (indium tin oxide, In{sub 2}O{sub 3}:Sn) coated on polyethylene terephthalate (PET) on a Corning glass substrate, and (c) ITO on a Corning glass substrate. These films are irradiated with 120 MeV Ag{sup +9} ions at fluences ranging from 3.0 × 10{sup 11} ions/cm{sup 2} to 3.0 × 10{sup 13} ions/cm{sup 2}. The structural, morphological, optical and electrical properties are studied via X-ray diffraction (XRD), atomic force microscopy (AFM), UV–Vis absorption spectroscopy and four-probe resistivity measurements, respectively. The ITO-PET electrode is found to exhibit superior conductivity and transmittance properties in comparison with the others after irradiation and, therefore, to be the most suitable for solar cell applications.

Effect of γ-irradiation on the electrical conductivity of some soda lime silicate glass containing blast furnace slag

International Nuclear Information System (INIS)

Elalaily, N.A.; Khalil, Magda M.I.; Ahmed, L.S.

2007-01-01

The effect of electric field strength on conduction in soda lime silicate glass doped with blast furnace slag with different concentration was studied and the value of jump distance was calculated. The structure and the mixed anion effect in the conductivity have been examined by measuring the electrical conductivity of glass samples at temperature ranging between 20 and 250 deg. C. The results showed that the electrical conductivity of the examined glasses are divided into three ranges depending on the temperature range. The first is from room temperature to about 49.5 deg. C, the second is at a temperature range of 60.3-104 deg. C where the glass shows a decrease in its conductivity with the increase in temperature. This was followed by another increase in the electrical conductivity with the increase in temperature. The results also showed that the glass becomes more insulating as the slag content increased. The effect of irradiation was also studied by exposing glass samples to two different irradiation doses. It can be noticed that irradiation causes an increase in the electrical conductivity, especially at high temperature. The results were discussed and correlated according to the molecular structure of the prepared glass

Enhanced AC conductivity and dielectric relaxation properties of polypyrrole nanoparticles irradiated with Ni12+ swift heavy ions

International Nuclear Information System (INIS)

Hazarika, J.; Kumar, A.

2014-01-01

In this paper, we report the 160 MeV Ni 12+ swift heavy ions (SHIs) irradiation effects on AC conductivity and dielectric relaxation properties of polypyrrole (PPy) nanoparticles in the frequency range of 42 Hz–5 MHz. Four ion fluences of 5 × 10 10 , 1 × 10 11 , 5 × 10 11 and 1 × 10 12 ions/cm 2 have been used for the irradiation purpose. Transport properties in the pristine and irradiated PPy nanoparticles have been investigated with permittivity and modulus formalisms to study the polarization effects and conductivity relaxation. With increasing ion fluence, the relaxation peak in imaginary modulus (M ″ ) plots shifts toward high frequency suggesting long range motion of the charge carriers. The AC conductivity studies suggest correlated barrier hopping as the dominant transport mechanism. The hopping distance (R ω ) of the charge carriers decreases with increasing the ion fluence. Binding energy (W m ) calculations depict that polarons are the dominant charge carriers

EFFECTS OF IRRADIATION ON THERMAL CONDUCTIVITY OF ALLOY 690 AT LOW NEUTRON FLUENCE

Directory of Open Access Journals (Sweden)

WOO SEOG RYU

2013-04-01

Full Text Available Alloy 690 has been selected as a steam generator tubing material for SMART owing to a near immunity to primary water stress corrosion cracking. The steam generators of SMART are faced with a neutron flux due to the integrated arrangement inside a reactor vessel, and thus it is important to know the irradiation effects of the thermal conductivity of Alloy 690. Alloy 690 was irradiated at HANARO to fluences of (0.7−28 × 1019n/cm2 (E>0.1MeV at 250°C, and its thermal conductivity was measured using the laser-flash equipment in the IMEF. The thermal conductivity of Alloy 690 was dependent on temperature, and it was a good fit to the Smith-Palmer equation, which modified the Wiedemann-Franz law. The irradiation at 250°C did not degrade the thermal conductivity of Alloy 690, and even showed a small increase (1% at fluences of (0.7∼28 × 1019n/cm2 (E>0.1MeV.

The influence of porosity on the thermal conductivity of irradiated UO2 fuel

International Nuclear Information System (INIS)

Bakker, K.; Kwast, H.; Cordfunke, E.H.P.

1994-12-01

The influence of porosity on the thermal conductivity of irradiated UO 2 fuel has been determined with the Finite Element Method (FEM). Light-microscopy photographs were made of the fuel. The pore shape and the pore distribution are entered in the FEM program from these photographs. The two dimensional (2D) thermal conductivity in the plane of the photograph is obtained from the FEM calculations. The 2D thermal conductivity, that has no physical meaning itself, is the lower limit of the three dimensional (3D) thermal conductivity. For three well defined pore shapes the relation is determined between the 2D thermal conductivity and the 3D thermal conductivity. From these computations a simple relation is obtained that transfers the 2D thermal conductivity into the 3D thermal conductivity, independent of the pore shape. The influence of porosity on the 3D thermal conductivity of irradiated UO 2 fuel and UO 2 fuel doped with Nb 2 O 5 was computed with the FEM. (orig.)

Identification of irradiated food. II. Identification of irradiated potato tubers by means of a test based on the variations of electrical conductivity

International Nuclear Information System (INIS)

Mazon Matanzo, M.P.; Fernandez Gonzalez, J.

1976-01-01

A method based on the measurement of the electrical conductivity of potato tubers is described. By means of this method irradiated tubers can be distinguished from IPC treated tubers and control tubers. The values of conductivity in the control and INC treated tubers were about 0,2 millimhos/cm, while those in the irradiated tubers oscillated about 0,17 millimhos/cm. (author) [es

In-situ ionic conductivity measurement of lithium ceramics under high energy heavy ion irradiation

International Nuclear Information System (INIS)

Nakazawa, Tetsuya; Noda, Kenji; Ishii, Yoshinobu; Ohno, Hideo; Watanabe, Hitoshi; Matsui, Hisayuki.

1992-01-01

To obtain fundamental information regarding the radiation damage in some lithium ceramics, e.g. Li 2 O, Li 4 SiO 4 etc., candidate of breeder materials exposed to severe irradiation environment, an in-situ experiment technique for the ionic conductivity measurement, which allows the specimen temperature control and the beam current monitoring, have been developed. This paper describes the features of an apparatus to measure in situ the ionic conductivity under the irradiation environment and presents some results of ionic conductivity measured for typical ceramic breeders using this apparatus. (J.P.N.)

Studies on potato irradiation in the G.D.R

International Nuclear Information System (INIS)

Luther, Th.; Huebner, G.; Grahn, Ch.; Doellstaedt, R.

1990-01-01

The studies of potato irradiation have been conducted in the framework of the National Food Irradiation Research Project for 4 years. Although in the G.D.R. the use of chemical sprout inhibitors is allowed, potato irradiation can be an alternative technique for potato processing. Before irradiation a wound healing period of approx. 2 weeks is absolutely necessary to protect the potatoes from Fusarium. The method that presents the minimum risk of damage is irradiation in containers. Economic evaluations for the irradiation of potatoes are also made. (author)

The effect of irradiation of the thermal conductivity of lithium ceramics

International Nuclear Information System (INIS)

Ethridge, J.L.; Baker, D.E.

1987-01-01

An apparatus for measuring the thermal conductivity of irradiated lithium ceramics to 900 0 C was designed, fabricated, and tested. Special attention was necessary in order to accommodate tritium released during the high-temperature measurements

Coupling ultraviolet light and ultrasound irradiation with Conductive-Diamond Electrochemical Oxidation for the removal of progesterone

International Nuclear Information System (INIS)

Vidales, María J. Martín de; Barba, Silvia; Sáez, Cristina; Cañizares, Pablo; Rodrigo, Manuel A.

2014-01-01

Highlights: • Single sonolysis and photolysis technologies entail a slight progesterone removal and nil mineralization. • Synergistic effects of irradiating UV light and US are clearly observed in the oxidation rate. • The energy required by CDSEO and CDSPEO prevents against their application. • CDSEO mainly favors the mass transfer of organics to the conductive-diamond surface. • CDPEO promotes the formation of radicals in the bulk solution. - Abstract: This work focusses on the improvement of the efficiency of Conductive Diamond Electrochemical Oxidation (CDEO) by coupling US and UV irradiation in the degradation of progesterone from wastewater. Results show that CDEO is a promising technology for the degradation of progesterone, just the opposite of that observed for single sonolysis and photolysis technologies, which only entail a slight removal of progesterone and nil mineralization. Coupling UV light and US irradiations with CDEO seems to have a very positive effect, improving results obtained by single CDEO very significantly. Conductive Diamond Sono Electrochemical Oxidation (CDSEO) mainly seems to improve the transfer of pollutants to the conductive-diamond surface, while Conductive Diamond Photo Electrochemical Oxidation (CDPEO) seems to promote the formation of radicals from oxidants produced electrochemically. Soft oxidation conditions are obtained with the single application of both irradiation technologies, whereas an efficient mineralization is attained with CDEO, CDSEO, CDPEO and Conductive Diamond Sono-Photo Electrochemical Oxidation (CDSPEO). However, the high energy demands of US irradiation technologies advices against the use of CDSEO and CDSPEO

Standard Practice for Conducting Irradiations at Accelerator-Based Neutron Sources

CERN Document Server

American Society for Testing and Materials. Philadelphia

1996-01-01

1.1 This practice covers procedures for irradiations at accelerator-based neutron sources. The discussion focuses on two types of sources, namely nearly monoenergetic 14-MeV neutrons from the deuterium-tritium T(d,n) interaction, and broad spectrum neutrons from stopping deuterium beams in thick beryllium or lithium targets. However, most of the recommendations also apply to other types of accelerator-based sources, including spallation neutron sources (1). Interest in spallation sources has increased recently due to their proposed use for transmutation of fission reactor waste (2). 1.2 Many of the experiments conducted using such neutron sources are intended to simulate irradiation in another neutron spectrum, for example, that from a DT fusion reaction. The word simulation is used here in a broad sense to imply an approximation of the relevant neutron irradiation environment. The degree of conformity can range from poor to nearly exact. In general, the intent of these simulations is to establish the fundam...

Enhanced AC conductivity and dielectric relaxation properties of polypyrrole nanoparticles irradiated with Ni{sup 12+} swift heavy ions

Energy Technology Data Exchange (ETDEWEB)

Hazarika, J.; Kumar, A., E-mail: ask@tezu.ernet.in

2014-08-15

In this paper, we report the 160 MeV Ni{sup 12+} swift heavy ions (SHIs) irradiation effects on AC conductivity and dielectric relaxation properties of polypyrrole (PPy) nanoparticles in the frequency range of 42 Hz–5 MHz. Four ion fluences of 5 × 10{sup 10}, 1 × 10{sup 11}, 5 × 10{sup 11} and 1 × 10{sup 12} ions/cm{sup 2} have been used for the irradiation purpose. Transport properties in the pristine and irradiated PPy nanoparticles have been investigated with permittivity and modulus formalisms to study the polarization effects and conductivity relaxation. With increasing ion fluence, the relaxation peak in imaginary modulus (M{sup ″}) plots shifts toward high frequency suggesting long range motion of the charge carriers. The AC conductivity studies suggest correlated barrier hopping as the dominant transport mechanism. The hopping distance (R{sub ω}) of the charge carriers decreases with increasing the ion fluence. Binding energy (W{sub m}) calculations depict that polarons are the dominant charge carriers.

Thermal conductivity profile determination in proton-irradiated ZrC by spatial and frequency scanning thermal wave methods

International Nuclear Information System (INIS)

Jensen, C.; Chirtoc, M.; Horny, N.; Antoniow, J. S.; Pron, H.; Ban, H.

2013-01-01

Using complementary thermal wave methods, the irradiation damaged region of zirconium carbide (ZrC) is characterized by quantifiably profiling the thermophysical property degradation. The ZrC sample was irradiated by a 2.6 MeV proton beam at 600 °C to a dose of 1.75 displacements per atom. Spatial scanning techniques including scanning thermal microscopy (SThM), lock-in infrared thermography (lock-in IRT), and photothermal radiometry (PTR) were used to directly map the in-depth profile of thermal conductivity on a cross section of the ZrC sample. The advantages and limitations of each system are discussed and compared, finding consistent results from all techniques. SThM provides the best resolution finding a very uniform thermal conductivity envelope in the damaged region measuring ∼52 ± 2 μm deep. Frequency-based scanning PTR provides quantification of the thermal parameters of the sample using the SThM measured profile to provide validation of a heating model. Measured irradiated and virgin thermal conductivities are found to be 11.9 ± 0.5 W m −1 K −1 and 26.7 ±1 W m −1 K −1 , respectively. A thermal resistance evidenced in the frequency spectra of the PTR results was calculated to be (1.58 ± 0.1) × 10 −6 m 2 K W −1 . The measured thermal conductivity values compare well with the thermal conductivity extracted from the SThM calibrated signal and the spatially scanned PTR. Combined spatial and frequency scanning techniques are shown to provide a valuable, complementary combination for thermal property characterization of proton-irradiated ZrC. Such methodology could be useful for other studies of ion-irradiated materials

Observation of He bubbles in ion irradiated fusion materials by conductive atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Fan, Hongyu [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China); Li, Ruihuan [School of Physics and Optoelectronic Engineering, Dalian University of Technology, Dalian 116024 (China); Yang, Deming [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China); School of Science, Changchun University of Science and Technology, Changchun, Jilin 130022 (China); Wu, Yunfeng; Niu, Jinhai; Yang, Qi [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China); Zhao, Jijun [School of Physics and Optoelectronic Engineering, Dalian University of Technology, Dalian 116024 (China); Liu, Dongping, E-mail: dongping.liu@dlnu.edu.cn [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian 116600 (China); Fujian Key Laboratory for Plasma and Magnetic Resonance, Department of Electronic Science, Aeronautics, School of Physics and Mechanical and Electrical Engineering, Xiamen University, Xiamen, Fujian 361005 (China)

2013-10-15

Using a non-destructive conductive atomic force microscope combined with the Ar{sup +} etching technique, we demonstrate that nanoscale and conductive He bubbles are formed in the implanted layer of single-crystalline 6H-SiC irradiated with 100 keV He{sup +}. We find that the surface swelling of irradiated SiC samples is well correlated with the growth of elliptic He bubbles in the implanted layer. First-principle calculations are performed to estimate the internal pressure of the He bubble in the void of SiC. Analysis indicates that nanoscale He bubbles acting as a captor capture the He atoms diffusing along the implanted layer at an evaluated temperature and result in the surface swelling of irradiated SiC materials.

Influence of composition, heat treatment and neutron irradiation on the electrical conductivity of copper alloys

Science.gov (United States)

Eldrup, M.; Singh, B. N.

1998-10-01

The electrical conductivity of three different types of copper alloys, viz. CuNiBe, CuCrZr and Cu-Al 2O 3 as well as of pure copper are reported. The alloys have undergone different pre-irradiation heat treatments and have been fission-neutron irradiated up to 0.3 dpa. In some cases post-irradiation annealing has been carried out. The results are discussed with reference to equivalent Transmission Electron Microscopy results on the microstructure of the materials. The CuNiBe has the lowest conductivity (⩽55% of that of pure Cu), and Cu-Al 2O 3 the highest (75-90% of pure Cu).

High energy (MeV) ion-irradiated π-conjugated polyaniline: Transition from insulating state to carbonized conducting state

International Nuclear Information System (INIS)

Park, S.K.; Lee, S.Y.; Lee, C.S.; Kim, H.M.; Joo, J.; Beag, Y.W.; Koh, S.K.

2004-01-01

High energy (MeV) C 2+ , F 2+ , and Cl 2+ ions were irradiated onto π-conjugated polyaniline emeraldine base (PAN-EB) samples. The energy of an ion beam was controlled to a range of 3-4.5 MeV, with the ion dosage varying from 1x10 12 to 1x10 16 ions/cm 2 . The highest dc conductivity (σ dc ) at room temperature was measured to be ∼60 S/cm for 4.5 MeV Cl 2+ ion-irradiated PAN-EB samples with a dose of 1x10 16 ions/cm 2 . We observed the transition of high energy ion-irradiated PAN-EB samples from insulating state to conducting state as a function of ion dosage based on σ dc and its temperature dependence. The characteristic peaks of the Raman spectrum of the PAN-EB samples were reduced, while the D-peak (disordered peak) and the G peak (graphitic peak) appeared as the ion dose increased. From the analysis of the D and G peaks of the Raman spectra of the systems compared to multiwalled carbon nanotubes, ion-irradiated graphites, and annealed carbon films, the number of the clusters of hexagon rings with conducting sp 2 -bonded carbons increased with ion dosage. We also observed the increase in the size of the nanocrystalline graphitic domain of the systems with increasing ion dosage. The intensity of normalized electron paramagnelic resonance signal also increased in correlation with ion dose. The results of this study demonstrate that π-conjugated pristine PAN-EB systems changed from insulating state to carbonized conducting state through high energy ion irradiation with high ion dosage

The conductivity behaviour of gamma-irradiated PEO-LiX electrolytes: Pt. 1

International Nuclear Information System (INIS)

Kronfli, Esam; Lovell, K.V.; Hooper, Alan; Neat, R.J.

1988-01-01

In an attempt to enhance the room temperature ionic conductivity of PEO-LiX films, samples have been exposed to gamma-irradiation at 78 0 C. The success with which cross-links have been introduced into the amorphous form has been evaluated from d.s.c. analysis and temperature-dependent conductivity data. Retardation of the recrystallisation event, associated with uncomplexed poly(ethylene oxide), does not occur over a range of total doses. Changes in overall conductivity levels for the PEO-LiCF 3 SO 3 ([EO units]/[Li] =9) system, indicate light cross-linking at 2.25 Mrad of exposure. However, higher doses result in a substantial amount of chain scission, leading eventually to poor mechanical properties. A similar study on PE 0 LiClO 4 ([EO units]/[Li] = 20) confirms that the above route is an ineffective method to improve room temperature conductivity. (author)

Influence of composition, heat treatment and neutron irradiation on the electrical conductivity of copper alloys

DEFF Research Database (Denmark)

Eldrup, Morten Mostgaard; Singh, B.N.

1998-01-01

The electrical conductivity of three different types of copper alloys, viz. CuNiBe, CuCrZr and Cu-Al(2)O(3) as well as of pure copper are reported. The alloys have undergone different pre-irradiation heat treatments and have been fission-neutron irradiated up to 0.3 dpa. In some cases post......-irradiation annealing has been carried out. The results are discussed with reference to equivalent Transmission Electron Microscopy results on the microstructure of the materials. The CuNiBe has the lowest conductivity (less than or equal to 55% of that of pure Cu), and Cu-Al(2)O(3) the highest (75-90% of pure Cu). (C...

Ion beam irradiation as a tool to improve the ionic conductivity in solid polymer electrolyte systems

Energy Technology Data Exchange (ETDEWEB)

Manjunatha, H., E-mail: h-manjunath@blr.amrita.edu; Kumaraswamy, G. N. [Department of Physics, Amrita Vishwa Vidyapeetham, Bengaluru-560 035 (India); Damle, R. [Department of Physics, Bangalore University, Bengaluru-560 056 (India)

2016-05-06

Solid polymer electrolytes (SPEs) have potential applications in solid state electronic and energy devices. The optimum conductivity of SPEs required for such applications is about 10{sup −1} – 10{sup −3} Scm{sup −1}, which is hard to achieve in these systems. It is observed that ionic conductivity of SPEs continuously increase with increasing concentration of inorganic salt in the host polymer. However, there is a critical concentration of the salt beyond which the conductivity of SPEs decreases due to the formation of ion pairs. In the present study, solid polymer thin films based on poly (ethylene oxide) (PEO) complexed with NaBr salt with different concentrations have been prepared and the concentration at which ion pair formation occurs in PEO{sub x}NaBr is identified. The microstructure of the SPE with highest ionic conductivity is modified by irradiating it with low energy O{sup +1} ion (100 keV) of different fluencies. It is observed that the ionic conductivity of irradiated SPEs increases by one order in magnitude. The increase in ionic conductivity may be attributed to the enhanced segmental motion of the polymer chains due to radiation induced micro structural modification.

60Co gamma irradiation effects on the the capacitance and conductance characteristics of Au/PMI/n-Si Schottky diodes

Science.gov (United States)

Tuğluoğlu, N.; Karadeniz, S.; Yüksel, Ö. F.; Şafak, H.; Kuş, M.

2015-08-01

In this work, the perylene-monoimide/n-Si (100) Schottky structures have been fabricated by spin coating process. We have studied the capacitance-voltage ( C- V) and conductance-voltage ( G- V) characteristics of the Au/perylene-monoimide/n-Si diodes at 500 kHz before and after 60Co γ-ray irradiation. The effects of 60Co γ -ray irradiation on the electrical characteristics of a perylene-monoimide/n-Si Schottky diode have been investigated. A decrease both in the capacitance and conductance has been observed after 60Co γ -ray irradiation. This has been attributed to a decrease in the net ionized dopant concentration that occurred as a result of 60Co γ-ray irradiation. Some contact parameters such as barrier height (Φ B ) interface state density ( N ss ) and series resistance ( R s ) have been calculated from the C- V and G- V characteristics of the diode before and after irradiation. It has been observed that the Φ B and N ss values are decreased after the applied radiation, while the R s value is increased.

The effect of low temperature neutron irradiation and annealing on the thermal conductivity of advanced carbon-based materials

International Nuclear Information System (INIS)

Barabash, V.; Mazul, I.; Latypov, R.; Pokrovsky, A.; Wu, C.H.

2002-01-01

Several carbon-based materials (carbon fibre composites NB 31, NS 31 and UAM-92, doped graphite RGTi-91), were irradiated at about 90 deg. C in the damage dose range 0.0021-0.13 dpa. Significant reduction of the thermal conductivity of all materials was observed (e.g. at damage dose of ∼0.13 dpa the thermal conductivity degraded up to level of ∼2-3% of the initial values). However, saturation of this effect was observed starting at a dose of ∼0.06 dpa. The effect of annealing at 250 and 350 deg. C on the recovery of thermal conductivity of NB 31 and NS 31 was studied and it was shown this annealing can significantly improve thermal conductivity (∼2.5-3 times). The data on the degradation of the thermal conductivity after additional irradiation after annealing is also reported

Some conclusions of studies on irradiation of whole fish aboard fishing vessels

International Nuclear Information System (INIS)

Reinacher, E.; Ehlermann, D.A.E.

1978-01-01

Studies were conducted on irradiation of whole redfish and haddock (at 100 krad) and subsequent storage of the irradiated fish for up to approx. 30 days in ice. The fish were organoleptically evaluated at intervals during storage. The results show no significant difference in organoleptic quality between irradiated and non-irradiated samples during storage for [de

Drop and recovery of thermal conductivity of AlN upon UV irradiation

International Nuclear Information System (INIS)

AlShaikhi, A; Srivastava, G P

2007-01-01

We have performed calculations of the room-temperature thermal conductivity of oxygen contaminated aluminium nitride (AlN) by employing the Callaway model with a detailed account of three-phonon scattering processes. The role of Al vacancy and O substitution of N has been examined in the form of extended defects (clusters) and point defects. Our work provides support for the theoretical model proposed by Harris et al. [Phys. Rev. B. 47, 5428 (1993)] to explain the experimentally observed drop in the conductivity upon UV irradiation and its recovery upon UV removal and subsequent illumination of the sample with visible light at room temperature. With the reported oxygen concentration in the sample, the scattering of phonons from oxygen-related extended defects is found to be ineffective. Within the picture presented by Harris et al., the point impurity scattering parameter increases by around 17% upon UV irradiation of the sample at room temperature

Ionic conduction in 70-MeV C5+-ion-irradiated poly(vinylidenefluoride- co-hexafluoropropylene)-based gel polymer electrolytes

International Nuclear Information System (INIS)

Saikia, D.; Kumar, A.; Singh, F.; Avasthi, D.K.; Mishra, N.C.

2005-01-01

In an attempt to increase the Li + -ion diffusivity, poly(vinylidenefluoride-co-hexafluoropropylene)-(propylene carbonate+diethyl carbonate)-lithium perchlorate gel polymer electrolyte system has been irradiated with 70-MeV C 5+ -ion beam of nine different fluences. Swift heavy-ion irradiation shows enhancement in ionic conductivity at lower fluences and decrease in ionic conductivity at higher fluences with respect to unirradiated gel polymer electrolyte films. Maximum room-temperature (303 K) ionic conductivity is found to be 2x10 -2 S/cm after irradiation with a fluence of 10 11 ions/cm 2 . This interesting result could be attributed to the fact that for a particular ion beam with a given energy, a higher fluence provides critical activation energy for cross linking and crystallization to occur, which results in the decrease in ionic conductivity. X-ray-diffraction results show decrease in the degree of crystallinity upon ion irradiation at low fluences (≤10 11 ions/cm 2 ) and increase in crystallinity at higher fluences (>10 11 ions/cm 2 ). Analysis of Fourier-transform infrared spectroscopy results suggests the bond breaking at a fluence of 5x10 9 ions/cm 2 and cross linking at a fluence of 10 12 ions/cm 2 and corroborate conductivity and x-ray-diffraction results. Scanning electron micrographs exhibit increased porosity of the polymer electrolyte after ion irradiation

Effect of swift heavy ion (SHI) irradiation on transparent conducting oxide electrodes for dye-sensitized solar cell applications

Science.gov (United States)

Singh, Hemant Kr.; Avasthi, D. K.; Aggarwal, Shruti

2015-06-01

Transparent conducting oxides (TCOs) are used as electrodes in dye-sensitized solar cells (DSSCs) because of their properties such as high transmittance and low resistivity. In the present work, the effects of swift heavy ion (SHI) irradiation on various types of TCOs are presented. The objective of this study is to investigate the effect of SHI on TCOs. For the present study, three different types of TCOs are considered, namely, (a) FTO (fluorine-doped tin oxide, SnO2:F) on a Nippon glass substrate, (b) ITO (indium tin oxide, In2O3:Sn) coated on polyethylene terephthalate (PET) on a Corning glass substrate, and (c) ITO on a Corning glass substrate. These films are irradiated with 120 MeV Ag+9 ions at fluences ranging from 3.0 × 1011 ions/cm2 to 3.0 × 1013 ions/cm2. The structural, morphological, optical and electrical properties are studied via X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Vis absorption spectroscopy and four-probe resistivity measurements, respectively. The ITO-PET electrode is found to exhibit superior conductivity and transmittance properties in comparison with the others after irradiation and, therefore, to be the most suitable for solar cell applications.

Modeling of Photovoltaic System with Modified Incremental Conductance Algorithm for Fast Changes of Irradiance

Directory of Open Access Journals (Sweden)

Saad Motahhir

2018-01-01

Full Text Available The first objective of this work is to determine some of the performance parameters characterizing the behavior of a particular photovoltaic (PV panels that are not normally provided in the manufacturers’ specifications. These provide the basis for developing a simple model for the electrical behavior of the PV panel. Next, using this model, the effects of varying solar irradiation, temperature, series and shunt resistances, and partial shading on the output of the PV panel are presented. In addition, the PV panel model is used to configure a large photovoltaic array. Next, a boost converter for the PV panel is designed. This converter is put between the panel and the load in order to control it by means of a maximum power point tracking (MPPT controller. The MPPT used is based on incremental conductance (INC, and it is demonstrated here that this technique does not respond accurately when solar irradiation is increased. To investigate this, a modified incremental conductance technique is presented in this paper. It is shown that this system does respond accurately and reduces the steady-state oscillations when solar irradiation is increased. Finally, simulations of the conventional and modified algorithm are compared, and the results show that the modified algorithm provides an accurate response to a sudden increase in solar irradiation.

Cherry Irradiation Studies. 1984 annual report

International Nuclear Information System (INIS)

Eakin, D.E.; Hungate, F.P.; Tingey, G.L.; Olsen, K.L.; Fountain, J.B.; Burditt, A.K. Jr.; Moffit, H.R.; Johnson, D.A.; Lunden, J.D.

1985-04-01

Fresh cherries, cherry fruit fly larvae, and codling moth larvae were irradiated using the PNL cobalt-60 facility to determine the efficacy of irradiation treatment for insect disinfestation and potential shelf life extension. Irradiation is an effective disinfestation treatment with no significant degradation of fruit at doses well above those required for quarantine treatment. Sufficient codling moth control was achieved at projected doses of less than 25 krad; cherry fruit fly control, at projected doses of less than 15 krad. Dose levels up to 60 krad did not adversely affect cherry quality factors tested. Irradiation above 60 krad reduced the firmness of cherries but had no significant impact on other quality factors tested. Irradiation of cherries below 80 krad did not result in any significant differences in sensory evaluations (appearance, flavor, and firmness) in tests conducted at OSU. Irradiation up to 200 krad at a temperature of about 25 0 C (77 0 F) did not measurably extend shelf life. Irradiation at 500 krad at 25 0 C (77 0 F) increased mold and rotting of cherries tested. There is no apparent advantage of irradiation over low-temperature fumigation

Patterning of nanoparticulate transparent conductive ITO films using UV light irradiation and UV laser beam writing

International Nuclear Information System (INIS)

Solieman, A.; Moharram, A.H.; Aegerter, M.A.

2010-01-01

Indium tin oxide (ITO) thin film is one of the most widely used as transparent conductive electrodes in all forms of flat panel display (FPD) and microelectronic devices. Suspension of already crystalline conductive ITO nanoparticles fully dispersed in alcohol was spun, after modifying with coupling agent, on glass substrates. The low cost, simple and versatile traditional photolithography process without complication of the photoresist layer was used for patterning ITO films. Using of UV light irradiation through mask and direct UV laser beam writing resulted in an accurate linear, sharp edge and very smooth patterns. Irradiated ITO film showed a high transparency (∼85%) in the visible region. The electrical sheet resistance decrease with increasing time of exposure to UV light and UV laser. Only 5 min UV light irradiation is enough to decrease the electrical sheet resistance down to 5 kΩ□.

Current mapping of low-energy (120 eV) helium and hydrogen irradiated tungsten by conductive atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Fan, Hongyu [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian (China); Endo, Takashi [Nano-micro Materials Analysis Laboratory, Hokkaido University, Sapporo (Japan); Bi, Zhenghua; Yan, Weibin [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian (China); Ohnuki, Somei [Nano-micro Materials Analysis Laboratory, Hokkaido University, Sapporo (Japan); Yang, Qi; Ni, Weiyuan [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian (China); Liu, Dongping, E-mail: dongping.liu@dlnu.edu.cn [School of Physics and Materials Engineering, Dalian Nationalities University, Dalian (China)

2017-04-01

Both conductive atomic force microscopy (CAFM) and transmission electron microscopy have been used to characterize the defects or He bubbles in low-energy (120 eV) H and He irradiated tungsten (W). By a comparative study, we find that the current mapping from CAFM is very sensitive in the detection of nanometer-sized defects in low-energy H and He irradiated W. Our calculation confirms that the resistance change in H and He irradiated W is strongly affected by the distance between atomic force microscopy tip and defects/He bubbles. CAFM can accurately detect defects/He bubbles in the W surface layer, however, it is infeasible to measure them in the deep layer (>20 nm), especially due to the existence of defects in the surface layer.

Studies on irradiated BNFL culture medium for decontamination and longer storage

International Nuclear Information System (INIS)

Singh, Antaryami; Malodia, P.; Jain, S.K.; Ram Gopal

2001-01-01

The feasibility of gamma radiation for microbial decontamination and shelf-life extension of culture medium was studied. Changes in total viable count, coliform count and fungal count on exposure to 5, 10, 15, 20 and 25 kGy of gamma radiation were examined. The total viable counts were reduced on irradiation. Complete destruction of bacterial and fungal contamination was observed at 20 kGy. Studies were conducted to examine the changes in microbial contamination of the medium during storage. There was no post irradiation proliferation of microorganisms. Also, no significant change in the efficiency of the irradiated culture medium was observed. Thus, irradiation is extremely useful for longer storage and quality-assurance. (author)

Thermal conductivity of graphene with defects induced by electron beam irradiation

Science.gov (United States)

Malekpour, Hoda; Ramnani, Pankaj; Srinivasan, Srilok; Balasubramanian, Ganesh; Nika, Denis L.; Mulchandani, Ashok; Lake, Roger K.; Balandin, Alexander A.

2016-07-01

We investigate the thermal conductivity of suspended graphene as a function of the density of defects, ND, introduced in a controllable way. High-quality graphene layers are synthesized using chemical vapor deposition, transferred onto a transmission electron microscopy grid, and suspended over ~7.5 μm size square holes. Defects are induced by irradiation of graphene with the low-energy electron beam (20 keV) and quantified by the Raman D-to-G peak intensity ratio. As the defect density changes from 2.0 × 1010 cm-2 to 1.8 × 1011 cm-2 the thermal conductivity decreases from ~(1.8 +/- 0.2) × 103 W mK-1 to ~(4.0 +/- 0.2) × 102 W mK-1 near room temperature. At higher defect densities, the thermal conductivity reveals an intriguing saturation-type behavior at a relatively high value of ~400 W mK-1. The thermal conductivity dependence on the defect density is analyzed using the Boltzmann transport equation and molecular dynamics simulations. The results are important for understanding phonon - point defect scattering in two-dimensional systems and for practical applications of graphene in thermal management.We investigate the thermal conductivity of suspended graphene as a function of the density of defects, ND, introduced in a controllable way. High-quality graphene layers are synthesized using chemical vapor deposition, transferred onto a transmission electron microscopy grid, and suspended over ~7.5 μm size square holes. Defects are induced by irradiation of graphene with the low-energy electron beam (20 keV) and quantified by the Raman D-to-G peak intensity ratio. As the defect density changes from 2.0 × 1010 cm-2 to 1.8 × 1011 cm-2 the thermal conductivity decreases from ~(1.8 +/- 0.2) × 103 W mK-1 to ~(4.0 +/- 0.2) × 102 W mK-1 near room temperature. At higher defect densities, the thermal conductivity reveals an intriguing saturation-type behavior at a relatively high value of ~400 W mK-1. The thermal conductivity dependence on the defect density is

Study on the physiological activities of gamma-irradiated seafood cooking drips

International Nuclear Information System (INIS)

Jo, Eu Ri; Kim, Yeon Joo; Choi, Jong Il; Sung, Nak Yun; Jung, Pil Moon; Kim, Jae Hun; Song, Beom Seok; Yoon, Yo Han; Lee, Ju Woon; Lee, Ju Yeoun

2010-01-01

Cooking drips which were obtained as by-product after seafood processing in the food industries, still contain lost of proteins, carbohydrates, and other functional materials. This study was conducted to investigate the effect of gamma irradiation on the biological activities of seafood cooking drips. When the cooking drips of Hizikia fusiformis, Enteroctopus dofleini and Thunnus thynnus were irradiated, the antioxidant activities, whitening effect, and angiotensin I converting enzyme inhibition activity of the ethanol extract from seafood cooking drips were all increased by gamma irradiation. This was because of the increased extraction efficiency of available compounds by irradiation. These results suggested that the seafood cooking drips, wasted as by-products, can be used as functional compounds with gamma irradiation treatment

Study on the physiological activities of gamma-irradiated seafood cooking drips

Energy Technology Data Exchange (ETDEWEB)

Jo, Eu Ri; Kim, Yeon Joo; Choi, Jong Il; Sung, Nak Yun; Jung, Pil Moon; Kim, Jae Hun; Song, Beom Seok; Yoon, Yo Han; Lee, Ju Woon [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Lee, Ju Yeoun [Chonbuk National University, Jeonju (Korea, Republic of)

2010-03-15

Cooking drips which were obtained as by-product after seafood processing in the food industries, still contain lost of proteins, carbohydrates, and other functional materials. This study was conducted to investigate the effect of gamma irradiation on the biological activities of seafood cooking drips. When the cooking drips of Hizikia fusiformis, Enteroctopus dofleini and Thunnus thynnus were irradiated, the antioxidant activities, whitening effect, and angiotensin I converting enzyme inhibition activity of the ethanol extract from seafood cooking drips were all increased by gamma irradiation. This was because of the increased extraction efficiency of available compounds by irradiation. These results suggested that the seafood cooking drips, wasted as by-products, can be used as functional compounds with gamma irradiation treatment.

Enhancement of electrical conductivity in gamma irradiated cobalt ferrite nanoparticles

International Nuclear Information System (INIS)

Nawpute, Asha A.; Raut, A.V.; Babrekar, M.K.; Kale, C.M.; Jadhav, K.M.; Shinde, A.B.

2014-01-01

The cobalt ferrite nanoparticles were synthesized by sol-gel auto- combustion method, in which L-ascorbic acid was used as a fuel. The effect of gamma irradiation on the electrical resistivity of cobalt ferrite nanoparticles has been studied. The ferrite powder annealed at 550℃ was irradiated by gamma source 137 Cs. The synthesized nanoparticles were characterized by X-ray diffraction and DC resistivity. (author)

Experimental study associated to irradiation of FBR structural material, (4)

International Nuclear Information System (INIS)

1976-01-01

The study presents one of the bases to evaluate the results of the post-irradiation tests to conduct the thermal control tests related to the second JMTR irradiation (70M-61P) of the demestic austenitic stainless steels for the structural material of the FBR performed by Power Reactor and Nuclear Fuel Development Corporation. The thermal control specimens were given the temperature history which simulated that of the irradiation temperature in vacuum by the electrical furnance, and then the tensile, fatigue and Charpy impact tests were performed. The changes of the material properties caused by the thermal history were investigated. (auth.)

Forecasting of the lethality in cases of nonuniform accidental irradiation (experimental studies at external gamma irradiation of rats)

International Nuclear Information System (INIS)

Ingilizova, K.

1983-01-01

A model is suggested that enables the prediction of death probability for the body (L) within the whole lethality dose range (DL 0 -DL 100 ), on the basis of predetermined physical characteristics: in cases of uneven external wholebody irradiation. Some biological effects of 4 variants of uneven irradiation have been studied, i.e. ventro-dorsal (V-D), dorso-ventral (D-V), cranio-caudal (Cr-Ca) and caudo-cranial (Ca-Cr). The following basic conclusions have been drawn: 1. The study of the biological effects of uneven irradiation, when estimated by the lethality factor, points out the lower efficiency of the former, if compared to even irradiation. 2. The even irradiation lethality in the conducted experiments, according to the ALE data and the postradiation mortality dynamics, is determined basically by the damage of the bloodforming tissue and the animals die of bone marrow syndrome. 3. The uneven irradiation, estimated by the total weight factor, is of lower efficiency than the even one. 4. The radiation-induced hypoplasia of the studied organs is exponential in character. 5. An original model for predicting radiation mortality in cases of uneven irradiation has been constructed. The model gives the possibility of relating the alterations in the index of biological efficiency reduction to the wholebody irradiation factor, as well as to the two systems with highest radiosensitivity: red bone marrow and the small intestine. The model helps determining the numerical value of death probability, depending on the average body irradiation doses and the integral unevenness factors for RBM. (author)

Wholesomeness studies on irradiated foods. Past and future research within the Soviet Union

Energy Technology Data Exchange (ETDEWEB)

Zaytsev, A.N.; Shillinger, Yu.I.; Kamaldinova, Z.M.

1975-11-01

The concept of wholesomeness is based on the absence of induced radioactivity, conservation of the nutritive value of food, and absence of toxicological or mutagenic effects. The possible occurrence of Clostridium botulinum toxin in irradiated fish products is discussed. Evaluation of the nutritive value of irradiated food is discussed with regard to proteins and vitamins. Toxicity and mutagenicity studies are described. Feeding studies on the wholesomeness of irradiated food were conducted in the Soviet Union using potatoes, grain, dried fruits, meat, poultry, and fish. The need for further investigations on the biological value of irradiated foods is pointed out. (HLW)

Magnetic studies of current conduction and flux pinning in high-Tc cuprates: Virgin, irradiated, and oxygen deficient materials

International Nuclear Information System (INIS)

Thompson, J.R.; Civale, L.; Marwick, A.D.; Holtzberg, F.

1992-09-01

To increase the current density and pinning of magnetic flux in high temperature superconductors, defects with point-like and line-like geometries were created in controlled numbers using ion irradiation methods. Single crystals of Y 1 Ba 2 Cu 3 O 7 and Bi 2 Sr 2 Ca 1 Cu 2 0 8 superconductors were studied using dc magnetic methods. These studies showed greatly increased irreversibility in the vortex state magnetization and enhanced intragrain current density J c following irradiation. Linear defects, created by irradiation with energetic heavy ions, are particularly effective in pinning vortices at higher temperatures and magnetic fields. Further investigations of ''flux creep'' (the time dependence of magnetization) are well described by recent vortex glass and collective pinning theories. Complementary investigations have delineated the role of oxygen deficiency δ on pinning in aligned Y 1 Ba 2 Cu 3 O 7-δ materials

Defect studies in electron-irradiated ZnO and GaN

International Nuclear Information System (INIS)

Tuomisto, F.; Look, D.C.; Farlow, G.C.

2007-01-01

We present experimental results obtained with positron annihilation spectroscopy in room-temperature electron-irradiated n-type ZnO and GaN. The cation vacancies act as important compensating centers in 2 MeV electron-irradiated samples, even though their introduction rates are different by 2 orders of magnitude. In addition, negatively charged non-open volume defects that also compensate the n-type conductivity are produced together with the cation vacancies at similar introduction rates. The low introduction rates of compensating defects in ZnO demonstrate the radiation hardness of the material. Isochronal thermal annealings were performed to study the dynamics of the irradiation-induced defects. In 2 MeV electron-irradiated ZnO, all the defects introduced in the irradiation disappear already at 600 K, while 1100 K is needed in GaN. Several separate annealing stages of the defects are observed in both materials, the first at 400 K

Defect studies in electron-irradiated ZnO and GaN

Energy Technology Data Exchange (ETDEWEB)

Tuomisto, F. [Laboratory of Physics, Helsinki University of Technology, 02015 TKK Espoo (Finland)], E-mail: filip.tuomisto@tkk.fi; Look, D.C. [Semiconductor Research Center, Wright State University, Dayton, OH 45435 (United States); Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, OH 45433 (United States); Farlow, G.C. [Physics Department, Wright State University, Dayton, OH 45435 (United States)

2007-12-15

We present experimental results obtained with positron annihilation spectroscopy in room-temperature electron-irradiated n-type ZnO and GaN. The cation vacancies act as important compensating centers in 2 MeV electron-irradiated samples, even though their introduction rates are different by 2 orders of magnitude. In addition, negatively charged non-open volume defects that also compensate the n-type conductivity are produced together with the cation vacancies at similar introduction rates. The low introduction rates of compensating defects in ZnO demonstrate the radiation hardness of the material. Isochronal thermal annealings were performed to study the dynamics of the irradiation-induced defects. In 2 MeV electron-irradiated ZnO, all the defects introduced in the irradiation disappear already at 600 K, while 1100 K is needed in GaN. Several separate annealing stages of the defects are observed in both materials, the first at 400 K.

A Study on Conjugate Heat Transfer Analysis of Reactor Vessel including Irradiated Structural Heat Source

Energy Technology Data Exchange (ETDEWEB)

Yi, Kunwoo; Cho, Hyuksu; Im, Inyoung; Kim, Eunkee [KEPCO EnC, Daejeon (Korea, Republic of)

2015-10-15

Though Material reliability programs (MRPs) have a purpose to provide the evaluation or management methodologies for the operating RVI, the similar evaluation methodologies can be applied to the APR1400 fleet in the design stage for the evaluation of neutron irradiation effects. The purposes of this study are: to predict the thermal behavior whether or not irradiated structure heat source; to evaluate effective thermal conductivity (ETC) in relation to isotropic and anisotropic conductivity of porous media for APR1400 Reactor Vessel. The CFD simulations are performed so as to evaluate thermal behavior whether or not irradiated structure heat source and effective thermal conductivity for APR1400 Reactor Vessel. In respective of using irradiated structure heat source, the maximum temperature of fluid and core shroud for isotropic ETC are 325.8 .deg. C, 341.5 .deg. C. The total amount of irradiated structure heat source is about 5.41 MWth and not effect to fluid temperature.

Further study of the glassy low-temperature properties of irradiated crystalline quartz: neutron and electron irradiation

International Nuclear Information System (INIS)

Laermans, C.; Daudin, B.

1979-01-01

Recently it has been shown that a quartz crystal after light fast neutron irradiation shows low temperature hypersonic properties which are similar to those found in glasses although the sample was still crystalline. Additional measurements have been carried out in the neutron-irradiated sample and a sample irradiated with high energy electrons has also been investigated. (Fast neutron dose 6 x 10 18 n/cm 2 , 2 MeV electron dose 3 x 10 19 e/cm 2 ). A magnetic field up to 1.5 T was found to have no influence in the hypersonic saturation behaviour of the neutron-irradiated sample (9 GHz, 1.65 K) and thermal conductivity measurements are consistent with a number of two level systems (2 LS) an order of magnitude lower than in vitreous silica as found before. Low temperature hypersonic measurements as a function of acoustic intensity and temperature as well as thermal conductivity measurements give no evidence for the presence of 2 LS in the electron irradiated sample. Considering the damage created in both samples this indicates that 2 LS are probably not related to point defects

In situ characterization of thermal conductivities of irradiated solids by using ion beam heating and infrared imaging

Energy Technology Data Exchange (ETDEWEB)

Mondrik, Nicholas; Gigax, Jonathan; Wang, Xuemei; Price, Lloyd [Department of Nuclear Engineering, Texas A and M University, College Station, TX 77843 (United States); Wei, Chaochen [Materials Science and Engineering Department, Texas A and M University, College Station, TX 77843 (United States); Shao, Lin, E-mail: lshao@tamu.edu [Department of Nuclear Engineering, Texas A and M University, College Station, TX 77843 (United States); Materials Science and Engineering Department, Texas A and M University, College Station, TX 77843 (United States)

2014-08-01

We propose a method to characterize thermal properties of ion irradiated materials. This method uses an ion beam as a heating source to create a hot spot on sample surface. Infrared imaging is used as a surface temperature mapping tool to record hot zone spreading. Since ion energy, ion flux, and ion penetration depth can be precisely controlled, the beam heating data is highly reliable and repeatable. Using a high speed infrared camera to capture lateral spreading of the hot zone, thermal diffusivity can be readily extracted. The proposed method has advantages in studying radiation induced thermal property changes, for which radiation damage can be introduced by using an irradiating beam over a relatively large beam spot and beam heating can be introduced by using a focused testing beam over a relatively small beam spot. These two beams can be switched without breaking vacuum. Thus thermal conductivity changes can be characterized in situ with ion irradiation. The feasibility of the technique is demonstrated on a single crystal quartz substrate.

In situ characterization of thermal conductivities of irradiated solids by using ion beam heating and infrared imaging

International Nuclear Information System (INIS)

Mondrik, Nicholas; Gigax, Jonathan; Wang, Xuemei; Price, Lloyd; Wei, Chaochen; Shao, Lin

2014-01-01

We propose a method to characterize thermal properties of ion irradiated materials. This method uses an ion beam as a heating source to create a hot spot on sample surface. Infrared imaging is used as a surface temperature mapping tool to record hot zone spreading. Since ion energy, ion flux, and ion penetration depth can be precisely controlled, the beam heating data is highly reliable and repeatable. Using a high speed infrared camera to capture lateral spreading of the hot zone, thermal diffusivity can be readily extracted. The proposed method has advantages in studying radiation induced thermal property changes, for which radiation damage can be introduced by using an irradiating beam over a relatively large beam spot and beam heating can be introduced by using a focused testing beam over a relatively small beam spot. These two beams can be switched without breaking vacuum. Thus thermal conductivity changes can be characterized in situ with ion irradiation. The feasibility of the technique is demonstrated on a single crystal quartz substrate

Studies of blood irradiator application

International Nuclear Information System (INIS)

Li Wenhong; Lu Yangqiao

2004-01-01

Transfusion is an important means for medical treatment, but it has many syndromes such as transfusion-associated graft-versus-host disease, it's occurrence rate of 5% and above 90% death-rate. Now many experts think the only proven method is using blood irradiator to prevent this disease. It can make lymphocyte of blood product inactive, so that it can not attack human body. Therefore, using irradiation blood is a trend, and blood irradiator may play an important role in medical field. This article summarized study of blood irradiator application, including the meaning of blood irradiation, selection of the dose for blood irradiation and so on

Clinical and experimental studies on the sensorineural hearing loss caused by irradiation

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, M [Kobe Univ. (Japan). School of Medicine

1979-08-01

In our study, 43 patients whose ears were presumably irradiated, were examined periodically before and after the irradiation; 10 were found to be affected by the sensorineural hearing loss, and these 10 were classified into two types. Type I; Patients of this group had a hearing impairment during or soon after irradiation and usually revealed marked deterioration of bone conduction in high frequencies accompanied by worsening of air conduction in low frequencies. The impaired hearing of this group soon recovered to the pre-treatment level. Type II; Patients of this group developed a slow progressive sensorineural hearing loss. They noticed the deafness with tinnitus several months after irradiation. To clarify the mechanism of the sensorineural hearing loss, histopathological investigations were done using nembutal anesthetized guinea pigs which were irradiated in the confined ear region unilaterally. We also examined histopathologically one human temporal bone belonging to a patient who had been irradiated for middle ear carcinoma. The histopathology of the guinea pigs and human case revealed the following conclusions: Type I hearing loss may be caused by toxic labyrinthitis secondary to the radiation otitis media or by the aseptic labyrinthitis as the result of hyperemia and increased permeability of the irradiated blood vessels in the cochlea. Type II hearing loss may be caused by the late rediation response of the cochleal blood vessels i.e. by the vasculitis which gives rise to obliteration of the vascular lumen and affects the blood supply of the hair cells.

Clinical and experimental studies on the sensorineural hearing loss caused by irradiation

International Nuclear Information System (INIS)

Yamamoto, Matsunori

1979-01-01

In our study, 43 patients whose ears were presumably irradiated, were examined periodically before and after the irradiation; 10 were found to be affected by the sensorineural hearing loss, and these 10 were classified into two types. Type I; Patients of this group had a hearing impairment during or soon after irradiation and usually revealed marked deterioration of bone conduction in high frequencies accompanied by worsening of air conduction in low frequencies. The impaired hearing of this group soon recovered to the pre-treatment level. Type II; Patients of this group developed a slow progressive sensorineural hearing loss. They noticed the deafness with tinnitus several months after irradiation. To clarify the mechanism of the sensorineural hearing loss, histopathological investigations were done using nembutal anesthetized guinea pigs which were irradiated in the confined ear region unilaterally. We also examined histopathologically one human temporal bone belonging to a patient who had been irradiated for middle ear carcinoma. The histopathology of the guinea pigs and human case revealed the following conclusions: Type I hearing loss may be caused by toxic labyrinthitis secondary to the radiation otitis media or by the aseptic labyrinthitis as the result of hyperemia and increased permeability of the irradiated blood vessels in the cochlea. Type II hearing loss may be caused by the late rediation response of the cochleal blood vessels i.e. by the vasculitis which gives rise to obliteration of the vascular lumen and affects the blood supply of the hair cells. (author)

Building up Graphene-Based Conductive Polymer Composite Thin Films Using Reduced Graphene Oxide Prepared by γ-Ray Irradiation

Directory of Open Access Journals (Sweden)

Siyuan Xie

2013-01-01

Full Text Available In this paper, reduced graphene oxide (RGO was prepared by means of γ-ray irradiation of graphene oxide (GO in a water/ethanol mix solution, and we investigated the influence of reaction parameters, including ethanol concentration, absorbed dose, and dose rate during the irradiation. Due to the good dispersibility of the RGO in the mix solution, we built up flexible and conductive composite films based on the RGO and polymeric matrix through facile vacuum filtration and polymer coating. The electrical and optical properties of the obtained composite films were tested, showing good electrical conductivity with visible transmittance but strong ultraviolet absorbance.

Growth studies on Lens culinaris after gamma irradiation

International Nuclear Information System (INIS)

Ahmad, S.; Bokhari, F.S.; Shahnaz, F.

1996-01-01

A study on growth parameters was carried out on two varieties of Lens culinaris after gamma irradiation. Experiment was conducted at Botanical Garden, Bahauddin Zakariya University, Multan in 1993. The germination percentage, survival percentage, height, branch number, pods per plant and 100-seed weight decreased with the increasing dose of radiation. Comparing the two varieties, variety-86642 appeared more sensitive to radiation than variety-87528

High-temperature annealing of proton irradiated beryllium – A dilatometry-based study

Energy Technology Data Exchange (ETDEWEB)

Simos, Nikolaos, E-mail: simos@bnl.gov [Brookhaven National Laboratory, Upton, NY, 11973 (United States); Elbakhshwan, Mohamed; Zhong, Zhong; Ghose, Sanjit [Brookhaven National Laboratory, Upton, NY, 11973 (United States); Savkliyildiz, Ilyas [Rutgers University (United States)

2016-08-15

S−200 F grade beryllium has been irradiated with 160 MeV protons up to 1.2 10{sup 20} cm{sup −2} peak fluence and irradiation temperatures in the range of 100–200 °C. To address the effect of proton irradiation on dimensional stability, an important parameter in its consideration in fusion reactor applications, and to simulate high temperature irradiation conditions, multi-stage annealing using high precision dilatometry to temperatures up to 740 °C were conducted in air. X-ray diffraction studies were also performed to compliment the macroscopic thermal study and offer a microscopic view of the irradiation effects on the crystal lattice. The primary objective was to qualify the competing dimensional change processes occurring at elevated temperatures namely manufacturing defect annealing, lattice parameter recovery, transmutation {sup 4}He and {sup 3}H diffusion and swelling and oxidation kinetics. Further, quantification of the effect of irradiation dose and annealing temperature and duration on dimensional changes is sought. The study revealed the presence of manufacturing porosity in the beryllium grade, the oxidation acceleration effect of irradiation including the discontinuous character of oxidation advancement, the effect of annealing duration on the recovery of lattice parameters recovery and the triggering temperature for transmutation gas diffusion leading to swelling.

Study of the effect of neutron and electron irradiations on the low temperature thermal conductivity of germanium and silicon; Etude de l'effet des irradiations neutronique et electronique sur la conductibilite thermique aux basses temperatures du germanium et du silicium

Energy Technology Data Exchange (ETDEWEB)

Vandevyver, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-06-15

The main results obtained from this work are the following: 1 Neutron irradiation (at 300 deg. K) produces lattice defects in germanium and silicon, and a corresponding very large lowering of the thermal conductivity is observed in the low temperature region (4-300 ). The results obtained have been explained with the help of the following hypotheses: for silicon a scattering of phonons by the stress fields produced by the defects; for germanium, a supplementary scattering of the electron phonon type. 2 Annealing treatments carried out on these materials above 373 deg. K restored the thermal conductivity over the whole temperature range of the measurements (4-300 deg. K); in the case of both germanium and silicon there were two steps in the annealing process. 3 A study of the thermal conductivity of germanium (initially P or N) after an electronic irradiation showed that the scattering of phonons could depend on the state of charge of the defects thus produced. (author) [French] Les principaux resultats obtenus au cours de ce travail sont les suivants : 1 Les irradiations neutroniques (a 300 deg. K) introduisent des defauts de reseau dans le germanium et le silicium et l'on observe correlativement pour ces materiaux, une tres importante diminution de conductibilite thermique dans le domaine des basses temperatures (4-300 deg. K). Les resultats obtenus ont pu etre interpretes en admettant principalement: pour le silicium, une diffusion des phonons par les champs de contrainte dus aux defauts; pour le germanium, une diffusion additionnelle du type electron-phonon. 2 Des recuits effectues sur ces materiaux au-dessus de 373 deg. K ont montre une restauration de la conductibilite thermique dans tout l'intervalle de temperature de mesure (4-300 deg. K) et comportant pour le germanium et le silicium, deux etapes de recuit 3 L'etude de la conductibilite thermique de germanium (initialement N ou P) apres une irradiation electronique, a montre que la diffusion des phonons

Neutron Flux Characterization of Irradiation Holes for Irradiation Test at HANARO

Directory of Open Access Journals (Sweden)

Yang Seong Woo

2016-01-01

Full Text Available The High flux Advanced Neutron Application ReactOr (HANARO is a unique research reactor in the Republic of Korea, and has been used for irradiation testing since 1998. To conduct irradiation tests for nuclear materials, the irradiation holes of CT and OR5 have been used due to a high fast-neutron flux. Because the neutron flux must be accurately calculated to evaluate the neutron fluence of irradiated material, it was conducted using MCNP. The neutron flux was measured using fluence monitor wires to verify the calculated result. Some evaluations have been conducted, however, more than 20% errors have frequently occurred at the OR irradiation hole, while a good agreement between the calculated and measured data was shown at the CT irradiation hole.

Electrochemical Studies on Important Elements for Zirconium Recovery Form Irradiated Zircaloy-4 Cladding

International Nuclear Information System (INIS)

Park, J.; Sohn, S.; Hwang, I.S.

2015-01-01

Since Zircaloy cladding accounts for about 16 wt. % of used nuclear fuel assembly, decontamination process is required to reduce the final waste volume from spent nuclear fuel. To develop Zircaloy-4 electrorefining process as an irradiated Zircaloy cladding decontamination process, electrochemical studies on Sn, Cr, Fe and Co which are major or important elements in the irradiated cladding were conducted based on cyclic voltammetry in LiCl-KCl at 500 deg. C. Cyclic voltammetry for Sn, Fe, Cr and Co elements that should be eliminated was conducted and revealed that redox reactions of these ions are much simpler than Zr and more reductive than Zr. The reliability of cyclic voltammetry was verified by comparing diffusion coefficients and formal reduction potentials of these ions obtained in this study to previous studies. (authors)

Consumer acceptance of irradiated food

Energy Technology Data Exchange (ETDEWEB)

Loaharanu, P [Head, Food Preservation Section, Joint FAO/ IAEA Division of Nuclear Techniques in Food and Agriculture, Wagramerstr. 5, A-1400, Vienna (Austria)

1998-12-31

There was a widely held opinion during the 1970`s and 1980`s that consumers would be reluctant to purchase irradiated food, as it was perceived that consumers would confuse irradiated food with food contaminated by radionuclides. Indeed, a number of consumer attitude surveys conducted in several western countries during these two decades demonstrated that the concerns of consumers on irradiated food varied from very concerned to seriously concerned.This paper attempts to review parameters conducting in measuring consumer acceptance of irradiated food during the past three decades and to project the trends on this subject. It is believed that important lessons learned from past studies will guide further efforts to market irradiated food with wide consumer acceptance in the future. (Author)

Consumer acceptance of irradiated food

Energy Technology Data Exchange (ETDEWEB)

Loaharanu, P. [Head, Food Preservation Section, Joint FAO/ IAEA Division of Nuclear Techniques in Food and Agriculture, Wagramerstr. 5, A-1400, Vienna (Austria)

1997-12-31

There was a widely held opinion during the 1970`s and 1980`s that consumers would be reluctant to purchase irradiated food, as it was perceived that consumers would confuse irradiated food with food contaminated by radionuclides. Indeed, a number of consumer attitude surveys conducted in several western countries during these two decades demonstrated that the concerns of consumers on irradiated food varied from very concerned to seriously concerned.This paper attempts to review parameters conducting in measuring consumer acceptance of irradiated food during the past three decades and to project the trends on this subject. It is believed that important lessons learned from past studies will guide further efforts to market irradiated food with wide consumer acceptance in the future. (Author)

Consumer acceptance of irradiated food

International Nuclear Information System (INIS)

Loaharanu, P.

1997-01-01

There was a widely held opinion during the 1970's and 1980's that consumers would be reluctant to purchase irradiated food, as it was perceived that consumers would confuse irradiated food with food contaminated by radionuclides. Indeed, a number of consumer attitude surveys conducted in several western countries during these two decades demonstrated that the concerns of consumers on irradiated food varied from very concerned to seriously concerned.This paper attempts to review parameters conducting in measuring consumer acceptance of irradiated food during the past three decades and to project the trends on this subject. It is believed that important lessons learned from past studies will guide further efforts to market irradiated food with wide consumer acceptance in the future. (Author)

Investigation of the electrical conductivity of γ-irradiated sodium silicate glasses containing multivalence Cu ions

International Nuclear Information System (INIS)

Tawansi, A.; Basha, A.F.; El-Konsol, S.

1981-07-01

The present investigation deals with a study of the γ-radiation effects on the d.c. electrical resistivity (rho) of SiO 2 -Na 2 O-CaO glasses containing Cu 0 , Cu + , Cu 2+ and mixture of Cu + and Cu 2+ ions over the temperature (T) range from 300 to 630 0 K. The applicability of the polaron hopping conduction mechanism has been established from the reciprocal temperature dependence of 1n rho/T for the samples under investigation. The electrical resistivity is found to decrease by increasing the TM valancy which enhances the hoping process. The post-irradiation effect due to ionizing gamma-radiation is investigated within the frame work of the electron (and hole) trapping theory, and an average value of 0.45 is obtained for the parameter Δ, characterizing traps with an exponentially decreasing numbers below the conduction band. (author)

Studies of defects on ion irradiated diamond

Energy Technology Data Exchange (ETDEWEB)

Lai, P.F.; Prawer, S.; Spargo, A.E.C.; Bursill, L.A. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1996-12-31

It is known that diamond is amorphized or graphitized when irradiated above a critical dose. Above this critical dose, D{sub c}, the resistance R is found to drop very rapidly due to the formation of graphite regions which overlap at D{sub c} to form a semi-continuous electrically conducting pathway through the sample. One particularly interesting method of studying this transformation is electron energy-loss spectroscopy (EELS). Using EELS, the different phases of carbon can be identified and distinguished from each other using the extended energy-loss fine structure (EXELFS) of the core-loss part of the spectrum. EELS is a sensitive method for determining the electronic structure of small areas of a sample. In this paper, transmission electron microscopy (TEM) and EELS measurements of the ion irradiated diamond were combined in an attempt to correlate the microstructural nature of the ion-beam induced damage to the changes in the electrical and other properties. 7 refs., 1 tab., 2 figs.

Studies of defects on ion irradiated diamond

Energy Technology Data Exchange (ETDEWEB)

Lai, P F; Prawer, S; Spargo, A E.C.; Bursill, L A [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1997-12-31

It is known that diamond is amorphized or graphitized when irradiated above a critical dose. Above this critical dose, D{sub c}, the resistance R is found to drop very rapidly due to the formation of graphite regions which overlap at D{sub c} to form a semi-continuous electrically conducting pathway through the sample. One particularly interesting method of studying this transformation is electron energy-loss spectroscopy (EELS). Using EELS, the different phases of carbon can be identified and distinguished from each other using the extended energy-loss fine structure (EXELFS) of the core-loss part of the spectrum. EELS is a sensitive method for determining the electronic structure of small areas of a sample. In this paper, transmission electron microscopy (TEM) and EELS measurements of the ion irradiated diamond were combined in an attempt to correlate the microstructural nature of the ion-beam induced damage to the changes in the electrical and other properties. 7 refs., 1 tab., 2 figs.

Biochemical Studies on Camel Milk as a Radioprotector in Irradiated Rats

International Nuclear Information System (INIS)

Ali, S.E.

2008-01-01

This work, was conducted to evaluate the possible capability of camel milk, as a radioprotector in irradiated (4.0 Gy) rats. Two examinations were performed after two and four weeks post irradiation. γ-irradiation caused significant disorders in hematological, physiological parameters and liver cellular aspects. Drinking of camel milk induced no adverse effect on the tested parameters. Moreover, it minimized and ameliorated the radiation disorders

A Study on Structural Strength of Irradiated Spacer Grid for PWR Fuel

Energy Technology Data Exchange (ETDEWEB)

Jin, Y. G.; Baek, S. J.; Kim, D. S.; Yoo, B. O.; Ahn, S. B.; Chun, Y. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, J. I.; Kim, Y. H.; Lee, J. J. [KEPCO NF, Daejeon (Korea, Republic of)

2014-10-15

A fuel assembly consists of an array of fuel rods, spacer grids, guide thimbles, instrumentation tubes, and top and bottom nozzles. In PWR (Pressurized light Water Reactor) fuel assemblies, the spacer grids support the fuel rods by the friction forces between the fuel rods and springs/dimples. Under irradiation, the spacer grids supporting the fuel rods absorb vibration impacts due to the reactor coolant flow, and also bear static and dynamic loads during operation inside the nuclear reactor and transportation for spent fuel storage. Thus, it is important to understand the characteristics of deformation behavior and the change in structural strength of an irradiated spacer grid.. In the present study, the static compression test of a spacer grid was conducted to investigate the structural strength of the irradiated spacer grid in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. To evaluate the structural strength of an irradiated spacer grid, hot cell tests were carried out at IMEF of KAERI. The fuel assembly was dismantled and the irradiated spacer grid was obtained for the compression test. The apparatus for measuring the compression strength of the irradiated spacer grid was developed and installed successfully in the hot cell.

Electric conductivity of polyethylene during pulsed electron-beam irradiation at ETA

International Nuclear Information System (INIS)

Fiorito, R.B.; Miller, P.J.; Stern, S.H.

1986-01-01

The motivation for this work is two-fold: first, the authors want to understand the basic physics of the interaction of an intense electron beam with condensed matter. Intensity is the key word in the sense that many projectiles might act coherently or incoherently to alter significantly the medium through which they pass. During the pulse of an intense electron beam through a material which is ordinarily dielectric, the conductivity increases by 10 to 15 orders of magnitude. This effect is related to the promotion of charge carriers to the conduction band and to the mobility and lifetime of those carriers in that band. Therefore, there is a physically interesting system which is measurable in real time. It is a system which interrelates beam energy-deposition, charge-carrier concentration, material temperature, and carrier mobility. The second motivation for these experiments is methodological. If the authors can understand the relationship between conductivity and energy deposition, they might be able to develop this technique into a diagnostic of the dose-depth relationship in material subject to very-high dose and high dose-rate irradiation (≥ 1 Grad in ≤ 25 nsec). This relationship is inaccessible to measurement by means of conventional dosimetry. 14 references

Study of effect of composition, irradiation and quenching on ionic ...

Indian Academy of Sciences (India)

The electrolyte samples are also quenched at liquid nitrogen temperature and conductivity measurements are carried out. The ionic conductivity at room temperature exhibits a characteristic peak for the composition, = 46. Electron beam irradiation results in an increase in conductivity for all compositions by a factor of 2–3.

White spot syndrome virus inactivation study by using gamma irradiation

Science.gov (United States)

Heidareh, Marzieh; Sedeh, Farahnaz Motamedi; Soltani, Mehdi; Rajabifar, Saeed; Afsharnasab, Mohammad; Dashtiannasab, Aghil

2014-09-01

The present study was conducted to investigate the effect of gamma irradiation on white spot syndrome virus (WSSV). White spot syndrome virus is a pathogen of major economic importance in cultured penaeid shrimp industries. White spot disease can cause mortalities reaching 100% within 3-10 days of gross signs appearing. During the period of culture, immunostimulant agents and vaccines may provide potential methods to protect shrimps from opportunistic and pathogenic microrganisms. In this study, firstly, WSSV was isolated from infected shrimp and then multiplied in crayfish. WSSV was purified from the infected crayfish haemolymph by sucrose gradient and confirmed by transmission electron microscopy. In vivo virus titration was performed in shrimp, Penaeus semisulcatus. The LD50 of live virus stock was calculated 10 5.4/mL. Shrimp post-larvae (1-2 g) were treated with gamma-irradiated (different doses) WSSV (100 to 10-4 dilutions) for a period of 10 days. The dose/survival curve for irradiated and un-irradiated WSSV was drawn; the optimum dose range for inactivation of WSSV and unaltered antigenicity was obtained 14-15 kGy. This preliminary information suggests that shrimp appear to benefit from treatment with gammairradiated WSSV especially at 14-15 KGy.

A study on UV irradiated HDPE

International Nuclear Information System (INIS)

Sang Haibo; Liu Zimin; Wu Shishan; Shen Jian

2006-01-01

The structure and properties of HDPE irradiated by ultraviolet (UV) in ozone atmosphere were studied by FT-IR, XPS, gel, and water contact angle test. The oxygen-containing groups such as C=O, C-O and C(=O)O were introduced onto high density polyethylene (HDPE) chains through ultraviolet irradiation in ozone atmosphere, their content increased with the UV irradiation time. Under the same UV irradiation conditions, amount of the oxygen-containing groups introduced in ozone atmosphere was more than that in air atmosphere, indicating that the speed of oxygen-containing groups introduced through UV irradiation in ozone atmosphere was faster than that in air. Therefore, HDPE could be quickly functionalized through UV irradiation in ozone atmosphere. There was no gel formed in the HDPE irradiated in ozone atmosphere. After UV irradiation, the water contact angle of HDPE decreased, and its hydrophilicity was improved, suggesting that the compatibility between the irradiated HDPE and polar polymer or inorganic fillers may be better. Compared with HDPE, the temperature of initial weight loss for irradiated HDPE decreased. The structure and properties of irradiated HDPE/CaCO 3 blend were also investigated. The results showed that the compatibility and interfacial action of the irradiated HDPE/CaCO 3 blend were improved compared to that of HDPE/CaCO 3 blend. The mechanical properties of irradiated HDPE/CaCO 3 blend increased with increasing irradiation time. (authors)

Study of the recrystallisation of irradiated uranium; Etude sur l'uranium irradie

Energy Technology Data Exchange (ETDEWEB)

Bloch, J; Mustelier, J P; Bussy, P; Blin, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

1- Study of the recrystallisation of irradiated uranium. The recrystallisation of uranium irradiated to a burnup level of 220 MWj/t, at a temperature of the order of 350 deg. C, has been investigated. The observations were made chiefly by means of micrography an hardness measurements. If the irradiated metal is compared with a cold-drawn metal showing the same shearing of the twinned crystals, and therefore the same rate of plastic deformation, as the irradiated metal, it is noted that the restoring of the irradiated metal takes place at a considerably higher temperature than that of the cold-drawn metal. Pre-crystallisation is very much delayed. Only, a passage of the {alpha}-{beta} transformation point quickly wipes out irradiation effect. 2- Hardening of uranium by irradiation. Using hardness measurements we have studied more especially the effect of very weak irradiations on uranium (integrated flux < 10{sup 16} nvt). The hardness does not increase linearly with the flux, but a period of incubation is observed probably representing the time necessary for saturation of the dislocations. (author)Fren. [French] 1- Etude de la recristallisation de l'uranium irradie. On a etudie la recristallisation d'uranium irradie jusqu'a un taux de combustion de 220 MWj/t a une temperature de l'ordre de 350 deg. C. Les observations ont ete faites principalement a l'aide de la micrographie et de la durete. Si l'on compare le metal irradie avec un metal ecroui presentant le meme cisaillement des macles, donc le meme taux de deformation plastique que le metal irradie, on constate que la restauration du metal irradie se fait a une temperature notablement superieure a celle du metal ecroui. La recristallisation est tres retardee. Seul, un passage du point de transformation {alpha}-{beta} efface rapidement l'effet de l'irradiation. 2- Durcissement de l'uranium par irradiation. Nous avons, a l'aide de la durete, etudie plus particulierement l'effet de tres faibles irrtions sur l

Gemstone color enhancement by electron beam irradiation-A preliminary study

International Nuclear Information System (INIS)

Sarada Idris; Zulkafli Ghazali; Shamshad Ahmad; Mohd Suhaimi Jusoh

2010-01-01

Treatment of gemstones has been going on for hundreds of years for enhancing color and clarity of gems devoid of these attributes. Whereas previous practices included fraudulent or otherwise processes to achieve the color enhancement, the ionizing radiation has proven to be a reliable and reproducible technique. Three types of irradiation processes include exposure to gamma radiation, electron beam irradiation and the nuclear power plants. Electron Beam Irradiation of Gemstone is a technique in which a gemstone is exposed to highly ionizing radiation electron beam to knock off electrons to generate color centers culminating in introduction of deeper colors. The color centers may be stable or unstable. Below 9 MeV, normally no radioactivity is introduced in the exposed gems. A study was conducted at Electron Beam Irradiation Centre (Alurtron) for gemstone color enhancement by using different kind of precious gemstones mined in Pakistan and elsewhere. The study shows that EB Irradiation not only enhances the color but also improves the clarity of the gemstones. The treated stones included kunzite tourmaline topaz quartz aquamarine and cultured pearls. Doses ranging from 25 kGy to 200 kGy were employed to assess the influence of doses on color and clarity and to select the optimum doses. The samples used included both the rough and the faceted gems. It is concluded that significant revenue generation is associated with the enhancement of the color in clarity of gemstones which are available at very cheap price in the world market. (author)

The effect of gamma irradiation on thermoelectric power and thermal conductivity of Ln0.01Sn0.99Se (Ln-Pr,Tb,Er) single crystals

International Nuclear Information System (INIS)

Guseynov, D.I.; Murguzov, M.I.; Ismaylov, Sh.S.; Mamedova, R.F.

2013-01-01

The present paper contains research results on the effect of gamma irradiation on thermal electromotive force and thermal conductivity of Ln 0 .01Sn 0 .99Se (Ln-Pr,Tb,Er) crystals. It is studied some electrical properties of the samples obtained before and after irradiation in a wide temperature range (80-420 K). As a source it was used an isotope 60Co with photon energies 1.25 MeV, the radiation dose was 65 Mrad

Thermal conductivity reduction of tungsten plasma facing material due to helium plasma irradiation in PISCES using the improved 3-omega method

Energy Technology Data Exchange (ETDEWEB)

Cui, Shuang [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Simmonds, Michael [Department of Physics, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Energy Research, University of California, San Diego, La Jolla, CA 92093 (United States); Qin, Wenjing; Ren, Feng [School of Physics and Technology, Wuhan University, Wuhan, Hubei 430072 (China); Tynan, George R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Energy Research, University of California, San Diego, La Jolla, CA 92093 (United States); Doerner, Russell P. [Center for Energy Research, University of California, San Diego, La Jolla, CA 92093 (United States); Chen, Renkun, E-mail: rkchen@ucsd.edu [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Center for Energy Research, University of California, San Diego, La Jolla, CA 92093 (United States)

2017-04-01

The near-surface region of plasma facing material (PFM) plays an important role in thermal management of fusion reactors. In this work, we measured thermal conductivity of tungsten (W) surface layers damaged by He plasma in PISCES at UCSD. We studied the damage effect on both bulk, and thin film, W. We observed that the surface morphology of both bulk and thin film was altered after exposure to He plasma with the fluence of 1 × 10{sup 26} m{sup −2} (bulk) and 2 × 10{sup 24} m{sup −2} (thin film). Transmission electron microscopy (TEM) analysis reveals that the depth of the irradiation damaged layer was approximately 20 nm on the bulk W exposed to He plasma at 773 K for 2000 s. In order to measure the thermal conductivity of this exceedingly thin damaged layer in the bulk W, we adopted the well-established ‘3-omega’ method and employed novel nanofabrication techniques to improve the measurement sensitivity. For the damaged W thin film sample, we measured the reduction in electrical conductivity and used the Wiedemann-Franz (W-F) law to extract the thermal conductivity. Results from both measurements show that thermal conductivity in the damaged layers was reduced by at least ∼80% compared to that of undamaged W. This large reduction in thermal conductivity can be attributed to the scattering of electrons, the dominant heat carriers in W, caused by defects introduced by He plasma irradiation.

Saturation behavior of irradiation hardening in F82H irradiated in the HFIR

Energy Technology Data Exchange (ETDEWEB)

Hirose, T. [Blanket Engineering Group, Japan Atomic Energy Agency, Naka, Ibaraki (Japan); Shiba, K.; Tanigawa, H.; Ando, M. [Japan Atomic Energy Agency, Tokai-mura, Naga-gun, Ibaraki-ken (Japan); Klueh, R.L. [Oak Ridge National Laboratory, TN (United States); Stoller, R. [ORNL - Oak Ridge National Laboratory, Materials Science and Technology Div., Oak Ridge, AK TN (United States)

2007-07-01

Full text of publication follows: Post irradiation tensile tests on reduced activation ferritic/martensitic steel, F82H have been conducted over the past two decades using Japan Materials Testing Reactor (JMTR) of JAEA, and Fast Flux Testing Facility (FFTF) of PNNL and High Flux Isotope Reactor (HFIR) of ORNL, USA, under Japan/US collaboration programs. According to these results, F82H does not demonstrate irradiation hardening above 673 K up to 60 dpa. The current study has been concentrated on hardening behavior at temperature around 573 K. A series of low temperature irradiation experiment has been conducted at the HFIR under the international collaborative research between JAEA/US-DOE. In this collaboration, the irradiation condition is precisely controlled by the well matured capsule designing and instrumentation. This paper summarizes recent results of the irradiation experiments focused on F82H and its modified steels compared with the irradiation properties database on F82H. Post irradiation tensile tests have been conducted on the F82H and its modified steels irradiated at 573 K and the dose level was up to 25 dpa. According to these results, irradiation hardening of F82H is saturated by 9 dpa and the as-irradiated 0.2 % proof stress is less than 1 GPa at ambient temperature. The deterioration of total elongation was also saturated by 9 dpa irradiation. The ductility of some modified steels which showed larger total elongation than that of F82H before irradiation become the same level as that of standard F82H steel after irradiation, even though its magnitude of irradiation hardening is smaller than that of F82H. This suggests that the more ductile steel demonstrates the more ductility loss at this temperature, regardless to the hardening level. The difference in ductility loss behavior between various tensile specimens will be discussed as the ductility could depend on the specimen dimension. (authors)

Study of neutron irradiation on F82H alloys by Mössbauer spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Huang, S.S., E-mail: h.shaosong@ht8.ecs.kyoto-u.ac.jp; Kitao, S.; Kobayashi, Y.; Yoshiie, T.; Xu, Q.; Sato, K.; Seto, M.

2015-01-15

The effects of neutron irradiation on F82H ferritic/martensitic stainless steel and its model alloys were studied by Mössbauer spectroscopy. The microstructural damage mechanisms of these alloys, during the void incubation period were interpreted using the short range order (SRO) parameters. Results show that within Fe–8Cr alloy, the atoms in the nearest neighbor (NN) of the Fe nuclei were inhomogeneous, prior to irradiation. A configuration trapping model of Cr supported the negative average SRO observed for the NN shells in our Fe–Cr alloys. We found that irradiation also accelerated the SRO in Fe–8Cr through a diffusion mechanism, where Cr atom repulsion was concentration dependent. Finally, comparative studies were conducted on F82H model alloys using the present Mössbauer measurements and our previously reported work on positron annihilation spectroscopy, which further established that irradiation of the alloys promoted the growth of a M{sub 23}C{sub 6} complex.

Irradiation of Gemstones using Electron Beam

International Nuclear Information System (INIS)

Sarada Idris; Mohd Suhaimi Jusoh; Siti Aiasah Hashim

2011-01-01

Gemstone irradiation treatment using radiation is one of the studies conducted in the ALURTRON. The purpose of radiation is to study the effects of radiation on the gems. Through studies conducted on freshwater pearls and stones such as Topaz, Kunzite, TOURMALINE, Aquamarine, Quartz and so on, electron beam irradiation method can highlight the jewel colors but also to reduce the effects of haze on gemstones. The dose of radiation used is 25 kGy to 200 kGy. (author)

A Study on Cell Size of Irradiated Spacer Grid for PWR Fuel

International Nuclear Information System (INIS)

Jin, Y. G.; Kim, G. S.; Ryu, W. S. and others

2014-01-01

The spacer grids supporting the fuel rods absorb vibration impacts due to the reactor coolant flow, and grid spring force decreases under irradiation. This reduction of contact force might cause grid-to-rod fretting wear. The fretting failure of the fuel rod is one of the recent significant issues in the nuclear industry from an economical as well as a safety concern. Thus, it is important to understand the characteristics of cell spring behavior and the change in size of grid cells for an irradiated spacer grid. In the present study, the dimensional measurement of a spacer grid was conducted to investigate the cell size of an irradiated spacer grid in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. To evaluate the fretting wear performance of an irradiated spacer grid, hot cell tests were carried out at IMEF of KAERI. Hot cell examinations include dimensional measurements for the irradiated spacer grid. The change of cell sizes was dependent on the direction of the spacer grids, leading to significant gap variations. It was found that the change in size of the cell springs due to irradiation-induced stress relaxation and creep during the fuel residency in the reactor core affect the contact behavior between the fuel rod and the cell spring

Studies on γ-irradiation-induced-degradation of chloramphenicol in aqueous solution

International Nuclear Information System (INIS)

Xie Fang; Ha Yiming; Wang Feng; Zhou Hongjie

2008-01-01

The irradiation-induced degradation of chloramphenicol by γ-rays in aqueous solution was studied and the radiolytical products were determined. The relationship among degradation rate, absorbed dose and initial concentration have been explored by comparing the position of maximum absorption peaks of chloramphenicol be- fore and after irradiation using high performance liquid chromatography. The identification of radiolytical products has been conducted using liquid chromatography tandem mass spectrometry. It has been found that the relationship among C/C 0 , absorbed dose and initial concentration can be fit with index curve. After irradiation, more than 30 radiolytical products with stable absorption below 278nm could be determined. 8 major radiolytical products with [M-H] - 353, 337, 335(A), 335(B), 319, 289, 127, 166, which are detected in several different conditions, have been picked up. Their possible structures are deducted. (authors)

Photoinduced conductivity in tin dioxide thin films

International Nuclear Information System (INIS)

Muraoka, Y.; Takubo, N.; Hiroi, Z.

2009-01-01

The effects of ultraviolet light irradiation on the conducting properties of SnO 2-x thin films grown epitaxially on TiO 2 or Al 2 O 3 single-crystal substrates are studied at room temperature. A large increase in conductivity by two to four orders of magnitude is observed with light irradiation in an inert atmosphere and remains after the light is removed. The high-conducting state reverts to the original low-conducting state by exposing it to oxygen gas. These reversible phenomena are ascribed to the desorption and adsorption of negatively charged oxygen species at the grain boundaries, which critically change the mobility of electron carriers already present inside grains by changing the potential barrier height at the grain boundary. The UV light irradiation provides us with an easy and useful route to achieve a high-conducting state even at low carrier density in transparent conducting oxides and also to draw an invisible conducting wire or a specific pattern on an insulating film.

Low frequency alternating current conduction and dielectric relaxation in polypyrrole irradiated with 100 MeV swift heavy ions of silver (Ag8+)

International Nuclear Information System (INIS)

Kaur, Amarjeet; Dhillon, Anju; Avasthi, D.K.

2013-01-01

Polypyrrole (PPY) films were prepared by electrochemical polymerization technique. The fully undoped samples were irradiated with different radiation fluences ranging from 10 10 to 10 12 ions cm −2 of 100 MeV silver (Ag 8+ ) ions. The temperature dependence of ac conductivity [σ m (ω)], dielectric constant (ε′) and dielectric loss (ε′′) of both irradiated as well as unirradiated samples have been investigated in 77–300 K. There exists typical Debye type dispersion. Giant increase in dielectric constant has been observed for irradiated samples which is attributed to polaronic defects produced during irradiation. - Graphical abstract: Display Omitted - Highlights: • Polypyrrole samples were prepared by electrochemical technique. • The fully undoped samples were irradiated with 100 MeV silver (Ag 8+ ) ions. • Giant increase in dielectric constant in irradiated samples is observed. • Dielectric behaviour is attributed to polaronic defects produced during irradiation

Effects of fast neutron irradiation on thermal conductivity of Li2O and LiAlO2

International Nuclear Information System (INIS)

Ethridge, J.L.; Baker, D.E.

1987-03-01

Li 2 O and LiAlO 2 are two candidates for solid breeder materials in the United States' Fusion Power Program. Critical to breeder design efforts are thermophysical data, the bulk of which have only recently become available, for unirradiated lithium ceramics. This paper expands the current limited database by presenting thermal conductivity data between 373-1173K for both materials following fast neutron irradiation. Samples were irradiated at 773-1173K to lithium burnups ≤11.5 /times/ 10 20 captures/cm 3 . Comparisons are made between these data and those from unirradiated archive samples of these same materials. 15 refs., 10 figs., 2 tabs

In situ transmission electron microscope studies of ion irradiation-induced and irradiation-enhanced phase changes

International Nuclear Information System (INIS)

Allen, C.W.

1992-01-01

Motivated at least initially by materials needs for nuclear reactor development, extensive irradiation effects studies employing transmission electron microscopes (TEM) have been performed for several decades, involving irradiation-induced and irradiation-enhanced microstructural changes, including phase transformations such as precipitation, dissolution, crystallization, amorphization, and order-disorder phenomena. From the introduction of commercial high voltage electron microscopes (HVEM) in the mid-1960s, studies of electron irradiation effects have constituted a major aspect of HVEM application in materials science. For irradiation effects studies two additional developments have had particularly significant impact; the development of TEM specimen holder sin which specimen temperature can be controlled in the range 10-2200 K and the interfacing of ion accelerators which allows in situ TEM studies of irradiation effects and the ion beam modification of materials within this broad temperature range. This paper treats several aspects of in situ studies of electron and ion beam-induced and enhanced phase changes and presents two case studies involving in situ experiments performed in an HVEM to illustrate the strategies of such an approach of the materials research of irradiation effects

Study on electric parameters of wild and cultivated cotton forms being in normal state and irradiated

International Nuclear Information System (INIS)

Nazirov, N.N.; Kamalov, N.; Norbaev, N.

1978-01-01

The radiation effect on electric conductivity of tissues in case of alternating current, electrical capacity and cell impedance has been studied. Gamma irradiation of seedlings results in definite changes of electric factors of cells (electric conductivity, electric capacity, impedance). It is shown that especially strong changes have been revealed during gamma irradiation of radiosensitive wild form of cotton plants. The deviation of cell electric factors from the standard depends on the violation of evolutionally composed ion heterogeneity and cell colloid system state, which results in changes in their structure and metabolism in them

Study of the recrystallisation of irradiated uranium

International Nuclear Information System (INIS)

Bloch, J.; Mustelier, J.P.; Bussy, P.; Blin, J.

1958-01-01

1- Study of the recrystallisation of irradiated uranium. The recrystallisation of uranium irradiated to a burnup level of 220 MWj/t, at a temperature of the order of 350 deg. C, has been investigated. The observations were made chiefly by means of micrography an hardness measurements. If the irradiated metal is compared with a cold-drawn metal showing the same shearing of the twinned crystals, and therefore the same rate of plastic deformation, as the irradiated metal, it is noted that the restoring of the irradiated metal takes place at a considerably higher temperature than that of the cold-drawn metal. Pre-crystallisation is very much delayed. Only, a passage of the α-β transformation point quickly wipes out irradiation effect. 2- Hardening of uranium by irradiation. Using hardness measurements we have studied more especially the effect of very weak irradiations on uranium (integrated flux 16 nvt). The hardness does not increase linearly with the flux, but a period of incubation is observed probably representing the time necessary for saturation of the dislocations. (author) [fr

Study on the changes in phyicochemical properties of seafood cooking drips by gamma ray irradiation

International Nuclear Information System (INIS)

Choi, Jong Il; Kim, Yeon Joo; Kim, Jae Hun; Yoon, Yo Han; Song, Beom Seok; Lee, Ju Woon; Chun, Byung Soo; Ahn, Dong Hyun; Lee, Ju Yeoun

2010-01-01

Cooking drips which were obtained as by-product after seafood processing in the food industries, still contain lots of proteins, carbohydrates, and other functional materials. But, the seafood cooking drips are easily contaminated because of its rich nutrients, and their color are very dark. This study was conducted to investigate the effect of gamma irradiation on the quality of seafood cooking drips including Hizikia fusiformis, Enteroctopus dofleini, and Thunnus thynnus. The Hunter's color values (L, Brightness) of H. fusiformis, and T.thynnus, were increased with increasing irradiation doses, showing becoming bright. The crude protein content and crude lipid content were increased by gamma irradiation. These results indicated that gamma irradiation increased extraction efficiency of available compounds in cooking drips

Fish irradiation

International Nuclear Information System (INIS)

Kovacs, J.; Tengumnuay, C.; Juangbhanich, C.

1970-01-01

Chub-mackerel was chosen for the study because they are the most common fish in Thailand. Preliminary investigations were conducted to determine the maximum radiation dose of gamma-rays by organoleptic tests. The samples were subjected to radiation at various doses up to 4 Mrad. Many experiments were conducted using other kinds of fish. The results showed that 1 Mrad would be the maximum acceptable dose for fish. Later, the influence of the radiation dose from 0.1-1 Mrad was studied in order to find the optimum acceptable dose for preservation of fish without off-flavour. For this purpose, the Hedonic scale was used. It was found that 0.2 and 0.5 Mrad gave the best result on Chub mackerel. The determinations of optimum dose, organoleptic, microbiological and trimethylamine content changes were done. The results showed that Chub mackerel irradiated at 0.2, 0.5 and 1 Mrad stored at 3 0 C for 71 days were still acceptable, on the contrary the untreated samples were found unacceptable at 14 days. The trimethylamine increment was significantly higher in the untreated samples. At 15 days storage, trimethylamine in the non-irradiated Chub-mackerel was about 10 times higher than the irradiated ones. At 51 and 79 days storage, about 13 times higher in the control samples than the irradiated samples except 0.1 Mrad. Only 2 times higher was found for the 0.1 Mrad. The microbiological results showed that the irradiation above 0.2 Mrad gave favorable extension of shelf-life of fish

A study of tritium behavior in lithium oxide by ion conductivity measurements

International Nuclear Information System (INIS)

Noda, Kenji; Ishii, Yoshinobu; Ohno, Hideo; Watanabe, Hitoshi

1989-01-01

Ion conductivity of lithium oxide (Li 2 O) irradiated with oxygen ions was measured to obtain information about the effects of irradiation on the behavior of lithium ions and tritium. The conductivity around 490 K decreased with the ion fluence, while around 440 K it increased. The decrease around 490 K and the increase around 440 K were assumed to be attributed to the F + centers and the unspecified radiation defects, respectively. From the point of view that the rate determinant in the mechanism of diffusion of lithium ions in Li 2 O leading to the ion conductivity is the same as that of tritium, the diffusivity of tritium is assumed to be as follows: the diffusivity of tritium is decreased by the F + centers in the range from 490 K to the temperature at which almost all of F + centers are recovered, while it is increased around 440 K by the unspecified radiation defects. In addition, effects of the irradiation on valence states of tritium (i.e., T + , T - ) were discussed in terms of the radiation defects. (orig.)

Monte Carlo studies for irradiation process planning at the Portuguese gamma irradiation facility

International Nuclear Information System (INIS)

Oliveira, C.; Salgado, J.; Botelho, M.L.M. Luisa; Ferreira, L.M.

2000-01-01

The paper describes a Monte Carlo study for planning the irradiation of test samples for microbiological validation of distinct products in the Portuguese Gamma Irradiation Facility. Three different irradiation geometries have been used. Simulated and experimental results are compared and good agreement is observed. It is shown that Monte Carlo simulation improves process understanding, predicts absorbed dose distributions and calculates dose uniformity in different products. Based on these results, irradiation planning of the product can be performed

Thermoluminescent and impedimetric studies on irradiated foodstuffs

International Nuclear Information System (INIS)

Mamoon, A.M.

2000-01-01

Several brands of different spices and milk powders were irradiated with relatively high doses of gamma radiation. Glow curves were produced upon heating these irradiated foodstuffs only. Study of the obtained spices glow curves revealed that the magnitude of these curves depends upon the dose received while the shape of the curves remains generally the same for the different doses and for the different spices. Previous studies had shown that the obtained thermoluminescence (TL) is due to dust particles carried by the spices. The TL studies show, furthermore, that different brands of the same spice are apparently contaminated with different amounts of dust or soil. The obtained TL from irradiated milk powders is apparently due to its mineral content. Different milk powders gave TL curves of different magnitudes for the same dose depending upon the milk brand. Impedimetric studies carried out irradiated potatoes show changes in impedance amplitude and phase angle. The results support earlier work on the use of TL to differentiate between irradiated and control foodstuffs, to assess the extent of spices contamination with soil-which perhaps reflects hygienic care-and that impedimetric measurements can distinguish irradiated from control potatoes

Study of irradiation effect on curcuma polyphenols

International Nuclear Information System (INIS)

Rejeb, Imen

2008-01-01

The present study was carried out to evaluate the effect of gamma irradiation on curcumin (Curcuma Longa rhizome) component, particularly the polyphenolic fraction. Powdered rhizome was irradiated at 0, 5, 10 and 15 KGy (dose rate of 6 KGy / H). Polyphenolics were extracted and total polyphenols conent (TPC) was quantified using the Folin-Ciocalteau method. The irradiation effect was also evaluated by the HPLC technique. The chromatographic analysis showed that the irradiated and non-irradiated curcumin spectrum gave similar data. The antioxidant and antibacterial activities of the phenolic extracts were also assessed. the anti oxidative potential of the sample was evaluated using two radical scavenging methods with DPPH and ABTS. The antimicrobial analysis showed that the phenolic extracts of curcumin inhibited the growth of the studied microorganisms. Our results showed that irradiated samples were not affected in terms of polyphenols content and characteristics. (Author)

U-turn type continuous irradiation method and device for radiation-irradiated capsule

International Nuclear Information System (INIS)

Kikuchi, Takayuki.

1997-01-01

A capsule to be irradiated is moved while being rotated in one of conveying shafts disposed in a reactor to conduct irradiation treatment. Then, the irradiated capsule is made U-turn in the reactor, inserted to the other conveying shaft and moved while being rotated to conduct irradiation treatment again, and then transported out of the reactor. The device comprises a rotational conveying shaft for moving the irradiated capsule while rotating it, a conveying gear for U-turning the irradiated capsule in the reactor and inserting it to the conveying shaft and a driving mechanism for synchronously rotating the conveying gear relative to the conveying shaft at a constant ratio. Mechanical time loss and manual operation time loss can be reduced upon loading and taking up of the irradiated capsule. Then, the amount of irradiation treatment per unit time is increased, and an optional neutron irradiation amount can be obtained thereby enabling to reduce operator's radiation exposure. (N.H.)

Food irradiation in Malaysia

International Nuclear Information System (INIS)

Mohd Ghazali Hj Abd Rahman.

1985-01-01

Food irradiation has recently been visited as a technology that can contribute to the solution of problems associated with food preservation of Malaysia's agriculture produce and products thereby improving the economic status of the rural sector. However, the history of food irradiation in Malaysia is very recent. Research carried out on food irradiation only began in 1974 as a result of the installation of a 60 Co facility (initially 10,000 Ci) at the National University of Malaysia. Since its installation several studies have been carried out pertaining to the food irradiation. Presently its development has been slow. Research in this area has been confined to laboratory scale and purely academic. This limitation is due to a number of reasons, among others are: a) limited number of facilities; b) lack of expertise to conduct its research; c) other preservation methods can be improved with lower capital output. An important step towards its development was made when Malaysia actively participated in the RCA/IAEA food irradiation project, viz. the irradiation of pepper which was carried out at the National University of Malaysia in the 80's. As a result of this venture, research and development activities in food irradiation have been geared toward semi-plot scale with the view ot commercialization in the future. In 1982, a group of researchers was formed to conduct feasibility studies using irradiation techniques in trying to overcome several problems associated with our local paddy and rice. Another group is being organized by the National University of Malaysia to look into the problems associated with the preservation of frozen shrimps. (author)

Studies on the preservation of food by gamma irradiation

International Nuclear Information System (INIS)

Kim, S.K.; Umeda, K.

1979-01-01

This work was conducted to investigate the effects of ionizing radiation on the preservation of potato. The Irish Cobbler potato tubers were irradiated at the doses of 7 krad and 15 krad of gamma ray of Co-60 at room temperature. When the potato tubers were stored under various conditions, the freshness and preservability of irradiated potato tubers were remarkably extended by 20, June. The results of this work are summarized as follows: The potato tubers applied with 15 krad of gamma ray were observed freshness without any shrinkage and defects. The potato tubers of control rotted and sprouted completely on 3, March. All tubers of them were cured at 7 0 C and relative humidity of 90% for a month before irradiation and they were treated at 18-20 0 C and RH 80% for 2 weeks after irradiation. They were stored at the above mentioned conditions. Reducing Sugar content of irradiated potato tubers was negligibly changed such as non-irradiated potato tubers along with an extended storage period, when they, as pre-and post-irradiation, were stored at 7 0 C and RH 90%. If they were treated at 18-20 0 C and RH 80% for 2 weeks after irradiation, reducing sugar content of the potato tubers was temporarily increased and then it was decreased as much as the former. As the result of microscopic test for the wound-peridom formation of potato tubers, the dark brown cork layer of wounded tuber of control was perfectly built up at about 2 weeks of the post wound, and starch particles have disappeared almost. The cork layer of irradiated potato tuber was formed at 3-4 weeks after wounded and also starch particles were not watched. The layers irradiated potato was observed the same as cork layer of sound potato. (author)

Brazilian Consumer views on food irradiation

NARCIS (Netherlands)

Behrens, J.H.; Barcellos, M.N.; Frewer, L.J.; Nunes, T.P.; Landgraf, M.

2009-01-01

This study investigated the consumer attitude to food irradiation in São Paulo, Brazil, through a qualitative research perspective. Three focus groups were conducted with 30 consumers, responsible for food choices and purchases. Both irradiated and nonirradiated food samples were served in the

Low frequency alternating current conduction and dielectric relaxation in polypyrrole irradiated with 100 MeV swift heavy ions of silver (Ag{sup 8+})

Energy Technology Data Exchange (ETDEWEB)

Kaur, Amarjeet, E-mail: amarkaur@physics.du.ac.in [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Dhillon, Anju [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Avasthi, D.K. [Inter University Accelerator Center (IUAC), Aruna Asaf Ali Road, New Delhi 110067 (India)

2013-07-15

Polypyrrole (PPY) films were prepared by electrochemical polymerization technique. The fully undoped samples were irradiated with different radiation fluences ranging from 10{sup 10} to 10{sup 12} ions cm{sup −2} of 100 MeV silver (Ag{sup 8+}) ions. The temperature dependence of ac conductivity [σ{sub m}(ω)], dielectric constant (ε′) and dielectric loss (ε′′) of both irradiated as well as unirradiated samples have been investigated in 77–300 K. There exists typical Debye type dispersion. Giant increase in dielectric constant has been observed for irradiated samples which is attributed to polaronic defects produced during irradiation. - Graphical abstract: Display Omitted - Highlights: • Polypyrrole samples were prepared by electrochemical technique. • The fully undoped samples were irradiated with 100 MeV silver (Ag{sup 8+}) ions. • Giant increase in dielectric constant in irradiated samples is observed. • Dielectric behaviour is attributed to polaronic defects produced during irradiation.

A study of positron irradiated porous silicon

International Nuclear Information System (INIS)

Huang Yuanming; Xue Qing; Zhai Baogai; Xu Aijun; Liu Shewen; Yu Weizhong

1998-01-01

The effect of positron irradiation on photoluminescence (PL) of porous silicon has been studied. After four hour positron irradiation, the red PL spectrum of porous silicon blue shifts into greenish spectral region, and a higher energy luminescence band is introduced into this blueshifted spectrum. The fourier transform infrared absorption experiment shows that the positron irradiation can cause further oxidization of porous silicon. A possible mechanism causing this change of PL spectra after positron irradiation is suggested

Experience with a pilot plant for the irradiation of sewage sludge; bacteriological and parasitological studies after irradiation

International Nuclear Information System (INIS)

Wizigmann, I.

1976-01-01

Reduction of viable micro-organisms could be achieved by irradiation of sewage sludge in a pilot plant ( 60 Co gamma-radiation 300 krad, 300 min.). The reduction amounted to an average of 2 log with Enterococces and total bacterial count and to 5 log with Enterobacteriaceae. Out of 23 sludge batches from digestor II, 21 were free of Salmonella after irradiation. Of 7 sludge batches from digester I with higher level of Enterobacteriaceae and Salmonellae 5 batches still contained Salmonella after treatment. By making some alterations in the pipe system and reloading futher Cobalt 60-sources the duration of irradiation could be reduced to 65 min. while maintaining the dose level of 300 krad. Employing this altered procedure 16 batches from digestor II and 4 from digestor I were irradiated to date. Only in one of 60 samples was Salmonella detectable. The hygenic effects of the irradiation unit were confirmed by means of a model experiment with bacterial pure cultures. Microorganisms of different species as well as strains of the same species differ in their radiation-sensitivity. Parasitological experiments were conducted with Ascaris suum ova. No embryonation was noted after radiation treatment at a dose of 300 krad. (author)

Electrical conductivity of In2O3 and Ga2O3 after low temperature ion irradiation; implications for instrinsic defect formation and charge neutrality level.

Science.gov (United States)

Vines, L; Bhoodoo, C; von Wenckstern, H; Grundmann, M

2017-12-13

The evolution of sheet resistance of n-type In 2 O 3 and Ga 2 O 3 exposed to bombardment with MeV 12 C and 28 Si ions at 35 K is studied in situ. While the sheet resistance of Ga 2 O 3 increased by more than eight orders of magnitude as a result of ion irradiation, In 2 O 3 showed a more complex defect evolution and became more conductive when irradiated at the highest doses. Heating up to room temperature reduced the sheet resistivity somewhat, but Ga 2 O 3 remained highly resistive, while In 2 O 3 showed a lower resistance than as deposited samples. Thermal admittance spectroscopy and deep level transient spectroscopy did not reveal new defect levels for irradiation up to [Formula: see text] cm -2 . A model where larger defect complexes preferentially produce donor like defects in In 2 O 3 is proposed, and may reveal a microscopic view of a charge neutrality level within the conduction band, as previously proposed.

Electrical conductivity of In2O3 and Ga2O3 after low temperature ion irradiation; implications for instrinsic defect formation and charge neutrality level

Science.gov (United States)

Vines, L.; Bhoodoo, C.; von Wenckstern, H.; Grundmann, M.

2018-01-01

The evolution of sheet resistance of n-type In2O3 and Ga2O3 exposed to bombardment with MeV 12C and 28Si ions at 35 K is studied in situ. While the sheet resistance of Ga2O3 increased by more than eight orders of magnitude as a result of ion irradiation, In2O3 showed a more complex defect evolution and became more conductive when irradiated at the highest doses. Heating up to room temperature reduced the sheet resistivity somewhat, but Ga2O3 remained highly resistive, while In2O3 showed a lower resistance than as deposited samples. Thermal admittance spectroscopy and deep level transient spectroscopy did not reveal new defect levels for irradiation up to 2 × 1012 cm-2. A model where larger defect complexes preferentially produce donor like defects in In2O3 is proposed, and may reveal a microscopic view of a charge neutrality level within the conduction band, as previously proposed.

Studies on some irradiated food products

International Nuclear Information System (INIS)

Mohammed, H.M.B.

1998-01-01

The aim of this investigation was to study the possibility of using some doses of gamma irradiation and cold storage (4+1 C) for improving the hygienic quality and shelf-life of some meat products ( beef luncheon, processed minced beef and fresh beef sausage). luncheon meat samples were irradiated at doses of 4,6,8,10 and 12 k Gy, while beef and sausage samples were subjected to 4,6 and 8 KGy gamma rays doses and the effects of irradiation on the organoleptic properties, microbiological aspects and the chemical composition were studied during cold storage (4+1 C) of samples. Attention was focussed on the changes occurred in the organoleptic properties of these products by the evaluation of sensory scores for appearance, color and odor of samples post irradiation and during cold storage (4+1 C). In addition, the effects of treatments and cold storage on the microbiological quality by the determination of total bacterial count, total psychropilic bacteria, total coliforms, total molds and yeasts, staphylococcus aureus, streptococcus faecalis as well as the detection of salmonellae were studied

A Study on the Thermal Neutron Filter for the Irradiation of Electronic Materials at HANARO

Energy Technology Data Exchange (ETDEWEB)

Yang, Seong Woo; Kim, Sung Ryul; Park, Seung Jae; Shin, Yoon Taeg; Cho, Man Soon; Cho, Kee Nam [KAERI, Daejeon (Korea, Republic of)

2016-05-15

The representative example is a technique of making the semiconductor with the transmutation using the pure Si. This NTD (Neutron Transmutation Doping) Si is used as a high-quality semiconductor because it has a uniform resistance. Likewise, the electronic materials are being investigated to improve the performance of material using the neutron irradiation method. The mechanism for reaction between the electronic materials and the neutrons depends on the energy of the neutron. Capturing reaction by thermal neutrons causes the transmutation and a lot of defects are made by fast neutrons. The study for the effect by such neutron energy is necessary to understand the performance improvement of the irradiated electronic materials. The thermal neutron filter was investigated to be used for the irradiation of electronic materials at HANARO. IP irradiation hole was selected and the irradiation device was designed. The analysis was conducted considering four candidate materials.

A NEXAFS and mass spectrometry study of cysteine, cystine and insulin irradiated with intermediate energy (0.8 keV) electrons

Energy Technology Data Exchange (ETDEWEB)

Simões, G., E-mail: simoes.grazieli@gmail.com [Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, 21941-909 Rio de Janeiro (Brazil); Rodrigues, F.N. [Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, 21941-909 Rio de Janeiro (Brazil); Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro, Maracanã, 20270-021 Rio de Janeiro (Brazil); Bernini, R.B. [Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, 21941-909 Rio de Janeiro (Brazil); Instituto Federal de Educação, Ciência e Tecnologia do Rio de Janeiro, Duque de Caxias, 25050-100 Rio de Janeiro (Brazil); Castro, C.S.C. [Instituto Nacional de Metrologia, Qualidade e Tecnologia – Inmetro, 25250-020 Rio de Janeiro (Brazil); Souza, G.G.B. de, E-mail: gerson@iq.ufrj.br [Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, 21941-909 Rio de Janeiro (Brazil)

2014-03-01

Highlights: • Structural modifications in sulfur containing biomolecules were investigated. • Significant modifications were observed in insulin irradiated NEXAFS spectra. • Degradation of insulin can be observed even at low temperature. • Alterations in insulin spectrum were characterized according to the state of sulfur. - Abstract: We have performed a NEXAFS (S 1s) and mass spectrometry study of solid samples of cysteine, cystine and insulin irradiated with 0.8 keV electrons. The measured mass spectra point out to processes of desulfurization, deamination, decarbonylation and decarboxylation in the irradiated biomolecules. Electron beam irradiation was also conducted at low temperatures in order to evaluate the possible contribution from thermal degradation processes. The NEXAFS spectra of irradiated cysteine and cystine did not show substantial changes when compared to the same spectra obtained using non-irradiated samples. The sulfur K-edge photoabsorption spectrum of irradiated insulin, however, showed clear modifications when compared to the spectrum of the non-irradiated protein, even when the irradiation was conducted at low temperature. Using an empirical combination of the photoabsorption spectra of cysteine and cystine (which are associated respectively with reduced and oxidized forms of sulfur) we have been able to reproduce the absorption spectrum of irradiated insulin.

Study of irradiation creep of vanadium alloys

Energy Technology Data Exchange (ETDEWEB)

Tsai, H.; Strain, R.V.; Smith, D.L. [Argonne National Lab., IL (United States)] [and others

1997-08-01

Thin-wall tubing was produced from the 832665 (500 kg) heat of V-4 wt.% Cr-4 wt.% Ti to study its irradiation creep behavior. The specimens, in the form of pressurized capsules, were irradiated in Advanced Test Reactor and High Flux Isotope Reactor experiments (ATR-A1 and HFIR RB-12J, respectively). The ATR-A1 irradiation has been completed and specimens from it will soon be available for postirradiation examination. The RB-12J irradiation is not yet complete.

Comparative study on disinfection potency of spore forming bacteria by electron-beam irradiation and gamma-ray irradiation

International Nuclear Information System (INIS)

Takizawa, Hironobu; Suzuki, Satoru; Suzuki, Tetsuya; Takama, Kozo; Hayashi, Toru; Yasumoto, Kyoden.

1990-01-01

Along with gamma-ray irradiation, electron-beam irradiation (EB) is a method to disinfect microorganisms which cause food decomposition and food-poisoning. The present study was undertaken to compare sterilization efficacy of EB and gamma-ray irradiation on bacterial spores and vegetative cells under various conditions. Spores of Bacillus pumilus, a marker strain for irradiation study, and Bacillus stearothermophilus known as a thermophilic bacteria were irradiated by electron-beam and gamma-ray separately at irradiation dose of 0 to 10 kGy on combination of wet/dry and aerobic/anaerobic conditions. Sterilization effect of irradiation on spores was evaluated by colony counting on agar plates. Results showed that both EB and gamma-ray irradiation gave sufficient sterilization effect on spores, and the sterilization effect increased exponentially with irradiation dose. The sterilization effect of gamma-ray irradiation was higher than that of EB in all cases. Higher disinfection effect was observed under aerobic condition. The present study suggests that oxygen supply in EB is more important than gamma-ray irradiation. No results suggesting that chlorine ion at 0.1 ppm (as available chlorine concentration) enhanced the sterilization efficacy of either EB or gamma-ray irradiation was obtained under any conditions examined. (author)

Comparative study on disinfection potency of spore forming bacteria by electron-beam irradiation and gamma-ray irradiation

Energy Technology Data Exchange (ETDEWEB)

Takizawa, Hironobu; Suzuki, Satoru; Suzuki, Tetsuya; Takama, Kozo [Hokkaido Univ., Hakodate (Japan). Faculty of Fisheries; Hayashi, Toru; Yasumoto, Kyoden

1990-10-01

Along with gamma-ray irradiation, electron-beam irradiation (EB) is a method to disinfect microorganisms which cause food decomposition and food-poisoning. The present study was undertaken to compare sterilization efficacy of EB and gamma-ray irradiation on bacterial spores and vegetative cells under various conditions. Spores of Bacillus pumilus, a marker strain for irradiation study, and Bacillus stearothermophilus known as a thermophilic bacteria were irradiated by electron-beam and gamma-ray separately at irradiation dose of 0 to 10 kGy on combination of wet/dry and aerobic/anaerobic conditions. Sterilization effect of irradiation on spores was evaluated by colony counting on agar plates. Results showed that both EB and gamma-ray irradiation gave sufficient sterilization effect on spores, and the sterilization effect increased exponentially with irradiation dose. The sterilization effect of gamma-ray irradiation was higher than that of EB in all cases. Higher disinfection effect was observed under aerobic condition. The present study suggests that oxygen supply in EB is more important than gamma-ray irradiation. No results suggesting that chlorine ion at 0.1 ppm (as available chlorine concentration) enhanced the sterilization efficacy of either EB or gamma-ray irradiation was obtained under any conditions examined. (author).

Conduction mechanism in electron beam irradiated Al/n-Si Schottky diode

International Nuclear Information System (INIS)

Vali, Indudhar Panduranga; Shetty, Pramoda Kumara; Mahesha, M.G.; Petwal, V.C.

2016-01-01

In the high energy physics experiments, silicon based diodes are used to fabricate radiation detector to detect the charged particles. The Schottky barrier diodes have been studied extensively to understand the behavior of metal semiconductor interface, since such interfaces have been utilized as typical contacts in silicon devices. Because of surface states, interfacial layer, microscopic clusters of metal-semiconductor phases and other effects, it is difficult to fabricate junctions with barriers near the ideal values predicted from the work functions of the two isolated materials, therefore measured barrier heights are used in the device design. In this work, the Al/n-Si Schottky contacts are employed to study the diode parameters (Schottky barrier height and ideality factor), where the Schottky contacts were fabricated on electron beam irradiated silicon wafers. The interface behavior between electron irradiated Si wafer and post metal deposition is so far not reported. This method could be an alternative way to tailor the Schottky barrier height (SBH) without subjecting semiconductor sample to pre chemical and/or post heat treatments during fabrication

Orbital irradiation for Graves' ophthalmopathy - Is it safe? A long-term follow-up study

NARCIS (Netherlands)

Wakelkamp, Iris M. M. J.; Tan, Hendra; Saeed, Peerooz; Schlingemann, Reinier O.; Verbraak, Frank D.; Blank, Leo E. C. M.; Prummel, Mark F.; Wiersinga, Wilmar M.

2004-01-01

Purpose: We evaluated the frequency of long-term complications of orbital irradiation (radiation-induced tumors, cataract, and retinopathy) in comparison with glucocorticoids. Design: We conducted a follow-up study in a cohort of 245 Graves' ophthalmopathy patients who had been treated with

In situ studies of the kinetics of surface topography development during ion irradiation

International Nuclear Information System (INIS)

Levinskas, R.; Pranevicius, L.

1996-01-01

Studies of the mechanical properties of the materials affected by 25-200 keV H + , He + , Ne + and Ar + ion irradiation in the range of fluences up to 2 · 10 17 cm -2 based on the analysis of acoustic emission signals, kinetics of the surface deformations measured by laser interferometric technique and the variations of the surface acoustic waves propagation velocity are conducted. The acoustic emissions source mechanisms under various ion irradiation conditions are discussed and relative contribution various possible mechanism are indicated. The correlation of experimental results obtained by different methods of analysis is done. (author). 11 refs, 5 figs

Irradiation preservation processing study of strawberry

International Nuclear Information System (INIS)

Xu Shihong; Zhu Zhaodi

1992-01-01

Radiation preservation processing of strawberry was studied. The results show that single seal processing or combining with irradiation processing under given doses is of no practical value, but only combining with chill processing can promote lengthening period of fresh keeping. Single irradiation processing under given doses provides not only good initial state, but also the beginning of bad development at top speed on microorganism. The composite processing of irradiation, chill and seal can supply extended shelf lifetime with optimum value of dual synergetic effect

Dielectric properties of proton irradiated PES

International Nuclear Information System (INIS)

Shah, Nilam; Singh, N.L.; Singh, K.P.

2005-01-01

Polyethersulfone films were irradiated with 3 MeV proton beam at fluences ranging from 10 13 to 10 15 ions/cm 2 . AC electrical properties of irradiated samples were studied in the frequency range 100 Hz to 1MHz by LCR meter. There is an exponential increase in conductivity with frequency but the effect of irradiation is not significant. The dielectric loss/constant are observed to change with fluence. (author)

Food irradiation: public attitudes at Argentina

International Nuclear Information System (INIS)

Croci, Clara A.; Curzio, Osvaldo A.

1999-01-01

The paper show the research and development activities conducted in the South National University in relation to the consumer attitude about irradiated foodstuff in general, and irradiated onions in particular. Marketing trials were conducted in three opportunities in Bahia Blanca and Buenos Aires cities. Two surveys were carried out with handouts distributed to the public: the first was a general survey intended to find out how much supermarket customers know about food preservation by means of ionizing irradiation, and how much interest the public and in buying onions treated with ionizing radiation; the second survey was carried out with the members of the public who had bought the treated onions. The form asked for the reason for buying irradiated onions, the opinion about the product, and whether the product would be purchase again. The results encourage the transference of irradiation technology with an important economic benefit for the productive sector. Also, these studies may be used as a useful tool to start the introduction of irradiated food in MERCORSUR countries. (author)

Study of Microhardness and Electrical Properties of Proton Irradiated Polyether sulfone

International Nuclear Information System (INIS)

Quresh, A.

2006-01-01

Polyethersulfone (PES) films were irradiated with 3 MeV proton beams in the fluence range 10 1 3-10 1 5 ions/cm 2 . The irradiated samples were characterized by a Vickers' microhardness tester at a load of 100-1000 mN, and electrical properties in the frequency range 100 Hz to 1MHz by an LCR meter. It is observed that microhardness increases as fluence increases up to the fluence of 10 1 4 ions/cm 2 and decreases on further increase of the fluence. This may be attributed to the fact that a cross linking phenomenon dominates up to the fluence of 10 1 4 ions/cm 2 . There is an exponential increase in conductivity and the effect of irradiation is significant at higher fluences. The dielectric constant/loss was found to change significantly due to irradiation. It has been found that dielectric response in both pristine and irradiated samples obey universal law is given by ε α f n -1.These results were corroborated with structural changes observed in FTIR spectra of pristine and irradiated samples

Theoretical models for electron conduction in polymer systems—I. Macroscopic calculations of d.c. transient conductivity after pulse irradiation

Science.gov (United States)

Bartczak, Witold M.; Kroh, Jerzy

The simulation of the transient d.c. conductivity in a quasi one-dimensional system of charges produced by a pulse of ionizing radiation in a solid sample has been performed. The simulation is based on the macroscopic conductivity equations and can provide physical insight into d.c. conductivity measurements, particularly for the case of transient currents in samples with internal space charge. We consider the system of mobile (negative) and immobile (positive) charges produced by a pulse of ionizing radiation in the sample under a fixed external voltage V0. The presence of space charge results in an electric field which is a function of both the spatial and the time variable: E( z, t). Given the space charge density, the electric field can be calculated from the Poisson equation. However, for an arbitrary space charge distribution, the corresponding equations can only be solved numerically. The two non-trivial cases for which approximate analytical solutions can be provided are: (i) The density of the current carriers n( z, t) is negligible in comparison with the density of immobile space charge N( z). A general analytical solution has been found for this case using Green's functions. The solutions for two cases, viz. the homogeneous distribution of space charge N( z) = N, and the non-homogeneous exponential distribution N( z) = A exp(- Bz), have been separately discussed. (ii) The space charge created in the pulse without any space charge present prior to the irradiation.

Studies on the mutagenic and cytogenetic effects of irradiated wheat in mice

International Nuclear Information System (INIS)

Reddy, P.P.; Reddi, O.S.; Ebenezer, D.N.; Naidu, N.V.; Goud, S.N.

1978-01-01

A series of experiments were conducted to test the mutagenic and cytogenetic potentials of freshly and stored irradiated wheat in mice. In the first series, the effects of feeding of CBA mice for 8 weeks with the diet containing 60% of wheat freshly irradiated ( 3 H/He mice were undertaken. Feeding of both freshly and stored irradiated wheat showed neither an increase in dominant lethals and chromosomal aberrations nor a reduction in germ cells. In another series, the reproductive performance of the CBA females fed stored irradiated (75 krad) wheat was investigated and it was observed that the average total number of litters and the litter size did not vary from those of the females fed unirradiated wheat. (author)

Thermal conductivities for sintered and sphere-pac Li2O and γ-LiAlO2 solid breeders with and without irradiation effects

International Nuclear Information System (INIS)

Liu, Y.Y.; Tam, S.W.

1984-07-01

Thermal conductivities (k, k/sub eff/) have been estimated for sintered and sphere-pac Li 2 O and γ-LiAlO 2 with and without neutron irradiation effects. The estimation is based on (1) data from unirradiated UO 2 , Li 2 O, and γ-LiAlO 2 ; (2) data from irradiated dielectric insulator materials; and (3) relatively simple physical models. Comparison of model predictions with limited ex- and in-reactor data found reasonable agreement, thus lending credence for their use in design applications. The impact of thermal conductivities on tritium breeding and power generation in fusion solid-breeder blankets is briefly highlighted

Boron nitride elastic and thermal properties. Irradiation effects

International Nuclear Information System (INIS)

Jager, Bernard.

1977-01-01

The anisotropy of boron nitride (BN) and especially thermal and elastic properties were studied. Specific heat and thermal conductivity between 1.2 and 300K, thermal conductivity between 4 and 350K and elastic constants C 33 and C 44 were measured. BN was irradiated with electrons at 77K and with neutrons at 27K to determine properties after irradiation [fr

Facilities for studying radiation damage in nonmetals during irradiation

International Nuclear Information System (INIS)

Levy, P.W.

1984-08-01

Two facilities have been developed for making optical absorption, luminescence and other measurements on a single sample before, during and after irradiation. One facility uses 60 Co gamma rays and the other 0.5 to 3 MeV electrons from an accelerator. Optical relays function as spectrophotometers, luminescenc detectors, etc. All radiation sensitive components are outside of walk-in irradiation chambers; all measurement control and data recording is computerized. Irradiations are made at controlled temperatures between 5K and 900 0 C. The materials studied include glasses, quartz, alkali halides (especially natural rock salt), organic crystals, etc. As determined from color center measurements the damage formation rate in all materials studied at 25 0 C or above is strongly temperature dependent. The defect concentration during irradiation is usually much greater than that measured after irradiation. The fraction of defects annealing after irradiation and the annealing rate usually increases as the irradiation temperature increases. The completed studies demonstrate that, in most cases, the extent of maximum damage and the damage formation and annealing kinetics can be determined only by making measurements during irradiation

Correlation between the structure modification and conductivity of 3 MeV Si ion-irradiated polyimide

International Nuclear Information System (INIS)

Sun Youmei; Zhu Zhiyong; Li Changlin

2002-01-01

The surface modification of the polyimide (PI/Kapton) films was carried out by 3 MeV Si + implantation to fluences ranging from 1x10 12 to 1.25x10 15 ions/cm 2 . Fourier transform infrared (FTIR), Raman and ultraviolet/visible (UV/Vis) spectroscopes were employed to investigate the chemical degradation of function groups in the irradiated layer. FTIR results show that the absorbance of typical function group decreases exponentially as a function of fluence. The damage cross-section of typical bonds of PI was evaluated from the FTIR spectra. Raman analysis shows the absorbed dose for destruction of all function groups is above 218 MGy. The red shifting of the absorption edge from UV to visible reveals the band gap closing which results from increase of the cluster size. The production efficiency of the chromophores was discussed according to UV/Vis analysis. Irradiation dramatically enhances the electrical conductivity and the sheet resistivity in our experiment descends nearly 10 orders of magnitude compared with its intrinsic value

Studies on the sterilization of soybean pod borer using nuclear irradiation technique

International Nuclear Information System (INIS)

Du Junling; Zhao Xiaoli

1994-01-01

A systematic study of soybean pod borer control by using the sterile technology of the nuclear irradiation was carried out. By changing the photo-period, the diapause was broken and the highest percentage of emergence was obtained with 18 hours illumination per day. The duration of diapause was reduced from 10 months to about 1 month and it took 40∼42 days to reproduce one generation. The suitable prescription of the artificial diet was selected. When the larvae were fed with soybean sprouts, the high survival rate was achieved with normal development. The suitable treatment period and irradiation dose were discussed. The irradiation treatment conducted two days before adult emergence with the irradiation dose of 120 Gy would give the best results, which showed that the emerged adult was normal, whereas the eggs laid were not able to be hatched. When releasing the adults emerged from the treated pupae into screen in the soybean field, the control effect of 88.1%∼99.0% was obtained, and the rate of seed-boring reduced from 10.1% to 0.1%∼1.3%. In the soybean field, its control effect was 86.56%

Property changes in graphite irradiated at changing irradiation temperature

International Nuclear Information System (INIS)

Price, R.J.; Haag, G.

1979-07-01

Design data for irradiated graphite are usually presented as families of isothermal curves showing the change in physical property as a function of fast neutron fluence. In this report, procedures for combining isothermal curves to predict behavior under changing irradiation temperatures are compared with experimental data on irradiation-induced changes in dimensions, Young's modulus, thermal conductivity, and thermal expansivity. The suggested procedure fits the data quite well and is physically realistic

Lymphoid cell kinetics under continuous low dose-rate gamma irradiation: A comparison study

Science.gov (United States)

Foster, B. R.

1975-01-01

A comparison study was conducted of the effects of continuous low dose-rate gamma irradiation on cell population kinetics of lymphoid tissue (white pulp) of the mouse spleen with findings as they relate to the mouse thymus. Experimental techniques employed included autoradiography and specific labeling with tritiated thymidine (TdR-(h-3)). The problem studied involved the mechanism of cell proliferation of lymphoid tissue of the mouse spleen and thymus under the stress of continuous irradiation at a dose rate of 10 roentgens (R) per day for 105 days (15 weeks). The aim was to determine whether or not a steady state or near-steady state of cell population could be established for this period of time, and what compensatory mechanisms of cell population were involved.

Wholesomeness studies in the International Food Irradiation Project

Energy Technology Data Exchange (ETDEWEB)

Elias, P S [International Food Irradiation Project, Federal Research Centre for Nutrition

1980-01-01

Despite more than 25 years of history as an effective food preservation method, food irradiation is still subject to strict legislative control in many countries and scientific investigations are required to provide reassurance as to the safety of irradiated food. The International Food Irradiation Project was set up on October 14, 1970 to facilitate the objective evaluation of the wholesomeness of irradiated foodstuffs. Its major activities are; (1) wholesomeness testing of irradiated foods, (2) research on and investigations into the methodology of wholesomeness testing, (3) dissemination of information, and (4) assisting national and international authorities in their consideration of acceptance of irradiated food. In particular, the project over the past nine years had been devoted to the provision of data to national health authorities and international bodies. Up to now, 23 studies were and are being carried out for the project under contract. Subjects for the studies include wheat, wheat flour, potatoes, fish, rice, mango, spices, dried dates, onions and cocoa beans.

Wholesomeness studies in the International Food Irradiation Project

International Nuclear Information System (INIS)

Elias, P.S.

1980-01-01

Despite more than 25 years history as an effective food preservation method, food irradiation is still subject to strict legislative control in many countries and it is required to carry out scientific investigations to reassure the safety of irradiated food. The International Food Irradiation Project was set up on October 14, 1970 to facilitate the objective evaluation of the wholesomeness of irradiated foodstuffs. Its major activities are; (1) wholesomeness testing of irradiated foods, (2) research on and investigations into the methodology of wholesomeness testing, (3) dissemination of information, and (4) assisting national and international authorities in their consideration of acceptance of irradiated food. In particular, the project over the past nine years had been devoted to the provision of data to national health authorities and international bodies. Up to now, 23 studies were and are being carried out for the project under contract. Subject to the studies include wheat, wheat flour, potatoes, fish, rice, mango, spices, dried dates, onions and cocoa beans. (Kitajima, A.)

COXPRO-II: a computer program for calculating radiation and conduction heat transfer in irradiated fuel assemblies

International Nuclear Information System (INIS)

Rhodes, C.A.

1984-12-01

This report describes the computer program COXPRO-II, which was written for performing thermal analyses of irradiated fuel assemblies in a gaseous environment with no forced cooling. The heat transfer modes within the fuel pin bundle are radiation exchange among fuel pin surfaces and conduction by the stagnant gas. The array of parallel cylindrical fuel pins may be enclosed by a metal wrapper or shroud. Heat is dissipated from the outer surface of the fuel pin assembly by radiation and convection. Both equilateral triangle and square fuel pin arrays can be analyzed. Steady-state and unsteady-state conditions are included. Temperatures predicted by the COXPRO-II code have been validated by comparing them with experimental measurements. Temperature predictions compare favorably to temperature measurements in pressurized water reactor (PWR) and liquid-metal fast breeder reactor (LMFBR) simulated, electrically heated fuel assemblies. Also, temperature comparisons are made on an actual irradiated Fast-Flux Test Facility (FFTF) LMFBR fuel assembly

Study for the identification of irradiated carbohydrate containing food

International Nuclear Information System (INIS)

Scherz, H.

1991-01-01

The study was undertaken to find radiation specific substances of carbohydrates and methods to detect those ones in irradiated food. Deoxycompounds have been found by irradiation of carbohydrates. It could be stated, that the formation of these substances was radiation specific. The irradiation of wheat for desinfestation was high actual at the moment of this study and therefore it was tried to find these deoxycompounds in irradiated potato starch and wheat flour. These substances were isolated and one of them was identified as w-hydroxymaltol. This substance was also found in irradiated wheat flour. The dependence between the amount of w-hydroxymaltol and the irradiation dosage was determined for both materials. (7 refs, 2 figs)

Electron microscope study of irradiated beryllium oxide

International Nuclear Information System (INIS)

Bisson, A.A.

1965-06-01

The beryllium oxide is studied first by fractography, before and after irradiation, using sintered samples. The fractures are examined under different aspects. The higher density sintered samples, with transgranular fractures are the most interesting for a microscopic study. It is possible to mark the difference between the 'pores' left by the sintering process and the 'bubbles' of gases that can be produced by former thermal treatments. After irradiation, the grain boundaries are very much weakened. By annealing, it is possible to observe the evolution of the gases produced by the reaction (n, 2n) and (n. α) and gathered on the grain boundaries. The irradiated beryllium oxide is afterwards studied by transmission. For that, a simple method has been used: little chips of the crushed material are examined. Clusters of point defects produced by neutrons are thus detected in crystals irradiated at the three following doses: 6 x 10 19 , 9 x 10 19 and 2 x 10 20 n f cm -2 at a temperature below 100 deg. C. For the irradiation at 6 x 10 19 n f cm -2 , the defects are merely visible, but at 2 x l0 20 n f cm -2 the crystals an crowded with clusters and the Kikuchi lines have disappeared from the micro-diffraction diagrams. The evolution of the clusters into dislocation loops is studied by a series of annealings. The activation energy (0,37 eV) calculated from the annealing curves suggests that it must be interstitials that condense into dislocation loops. Samples irradiated at high temperatures (650, 900 and 1100 deg. C) are also studied. In those specimens the size of the loops is not the same as the equilibrium size obtained after out of pile annealing at the same temperature. Those former loops are more specifically studied and their Burgers vector is determined by micro-diffraction. (author) [fr

Study of inhibition on lipid oxidation of irradiated pork

International Nuclear Information System (INIS)

Ha Yiming

2006-03-01

It was studied that the effect factors of irradiation dose, preservation temperature, oxygen content and antioxidant on lipid oxidation of irradiated pork. A mechanism was explained on lipid oxidation of irradiated pork. The results showed that irradiation might aggravate lipid oxidation of pork and that decreased preservation temperature and oxygen content of the packaging, added antioxidant also could effectively inhibit lipid oxidation of irradiated pork. (authors)

Effects of gamma irradiation on the performance of Jatropha (Jatropha curcas L.) accessions

Science.gov (United States)

Surahman, M.; Santosa, E.; Agusta, H.; Aisyah, S. I.; Nisya, F. N.

2018-03-01

This study aimed to assess the effects of mutation by using gamma ray on the performance of jatropha plants. The study was conducted at PAIR BATAN. Jatropha seeds obtained from the collection farm of SBRC LPPM IPB and PT Indocement Tunggal Prakarsa Tbk in Gunung Putri, Bogor, were irradiated. The irradiated seeds were grown in Jonggol Trial Farm of IPB. Gamma irradiation was conducted by using a GCM 4000A device. Treatments consisted of irradiation doses, irradiation methods, and accessions. Irradiation doses given were 175, 200, 225 Gy, and no irradiation (control). Irradiation methods consisted of acute, intermittent, and split-dose. Accessions used in this study were Dompu, Medan, Bima, Lombok, ITP II, IP2P, and Thailand. Results of the study were analysed until 5 months after planting showed that gamma ray mutation gave stimulating and inhibiting effects on similar traits. Irradiation dose of 225 Gy was good to be given in acute, intermittent, and split-dose methods. Irradiation effects were found to be significant in jatropha accessions. Effects of irradiation on production will be published soon.

Biochemical and Tissue Studies on Post Irradiation Recovery in Mammals

International Nuclear Information System (INIS)

Abdou, M.I.M.

2004-01-01

three main studies were performed in this thesis, namely, mortality and survival study, biochemical studies, and studies on tissue alterations cobalt-60 gamma irradiation for low let was used for the external whole body irradiation of the irradiated animal groups. a total number of animals of 722 virgin female adult wister rats of approximately the same age and weight were used for the three studies that were performed, including the control and irradiated animal groups. the animals were housed and kept with special care at fixed temperature, humidity and diet. the study on mortality and survival included 370 animals divided into control and groups irradiated with 4,5,6,7,8 and 9 Gy. this study was followed up for one year to record the number and date of animal deaths for the different irradiated groups. for the 8 and 9 Gy irradiated groups the follow up ended after 12 weeks and 11 days respectively when animal mortality reached 100%. the maximum percent mortality was noted at the second week (3.3,8,14 and 29%) for the 4,5,6 and 7 Gy irradiated groups respectively. for the 8 and 9 Gy irradiated groups, the maximum percent mortality was noted at the first week (42.9 and 90% respectively). regression equations were applied for the percent of mortality of the 5-8 Gy irradiated groups to estimate the LD 50/30, which was found to be 6.4 Gy

Consumer acceptance of irradiated food products: an apple marketing study

International Nuclear Information System (INIS)

Terry, D.E.; Tabor, R.L.

1990-01-01

This study was exploratory in nature, with emphasis on initial purchases and not repeat purchases or long-term loyalties to either irradiated or non-irradiated produce. The investigation involved the actual sale of irradiated and non-irradiated apples to consumers. Limited information about the process was provided, and apples were sold at roadside stands. Prices for the irradiated apples were varied while the price for the non-irradiated apples was held constant. Of these 228 West-Central Missouri shoppers, 101 (44%) bought no irradiated apples, 86 (38%) bought only irradiated apples, and 41 (18%) bought some of both types, Results of probit regressions indicated three significant independent variables. There was an inverse relationship between the price of irradiated apples and the probability of purchasing irradiated apples. There was a positive relationship between the purchasers’ educational level and the probability of purchasing irradiated apples. Predicted probabilities for belonging to categories in probit models were computed. Depending on particular equation specification, correctly placed were approximately 70 percent of the purchasers of the two categories--bought only non-irradiated apples, or bought some of both irradiated and non-irradiated apples or only irradiated apples. This study suggests that consumers may be interested in food irradiation as a possible alternative or supplement to current preservation techniques

In-situ high temperature irradiation setup for temperature dependent structural studies of materials under swift heavy ion irradiation

International Nuclear Information System (INIS)

Kulriya, P.K.; Kumari, Renu; Kumar, Rajesh; Grover, V.; Shukla, R.; Tyagi, A.K.; Avasthi, D.K.

2015-01-01

An in-situ high temperature (1000 K) setup is designed and installed in the materials science beam line of superconducting linear accelerator at the Inter-University Accelerator Centre (IUAC) for temperature dependent ion irradiation studies on the materials exposed with swift heavy ion (SHI) irradiation. The Gd 2 Ti 2 O 7 pyrochlore is irradiated using 120 MeV Au ion at 1000 K using the high temperature irradiation facility and characterized by ex-situ X-ray diffraction (XRD). Another set of Gd 2 Ti 2 O 7 samples are irradiated with the same ion beam parameter at 300 K and simultaneously characterized using in-situ XRD available in same beam line. The XRD studies along with the Raman spectroscopic investigations reveal that the structural modification induced by the ion irradiation is strongly dependent on the temperature of the sample. The Gd 2 Ti 2 O 7 is readily amorphized at an ion fluence 6 × 10 12 ions/cm 2 on irradiation at 300 K, whereas it is transformed to a radiation-resistant anion-deficient fluorite structure on high temperature irradiation, that amorphized at ion fluence higher than 1 × 10 13 ions/cm 2 . The temperature dependent ion irradiation studies showed that the ion fluence required to cause amorphization at 1000 K irradiation is significantly higher than that required at room temperature irradiation. In addition to testing the efficiency of the in-situ high temperature irradiation facility, the present study establishes that the radiation stability of the pyrochlore is enhanced at higher temperatures

Irradiation exposure modulates central opioid functions

International Nuclear Information System (INIS)

Dougherty, P.M.; Dafny, N.

1987-01-01

Exposure to low doses of gamma irradiation results in the modification of both the antinociceptive properties of morphine and the severity of naloxone-precipitated withdrawal in morphine-dependent rats. To better define the interactions between gamma irradiation and these opiate-mediated phenomena, dose-response studies were undertaken of the effect of irradiation on morphine-induced antinociception, and on the naloxone-precipitated withdrawal syndrome of morphine-dependent rats. In addition, electrophysiologic studies were conducted in rats after irradiation exposure and morphine treatment correlating with the behavioral studies. The observations obtained demonstrated that the antinociceptive effects of morphine as well as naloxone-precipitated withdrawal were modified in a dose-dependent manner by irradiation exposure. In addition, irradiation-induced changes in the evoked responses obtained from four different brain regions demonstrated transient alterations in both baseline and morphine-treated responses that may reflect the alterations observed in the behavioral paradigms. These results suggest that the effects of irradiation on opiate activities resulted from physiologic alterations of central endogenous opioid systems due to alterations manifested within peripheral targets

Irradiation exposure modulates central opioid functions

Energy Technology Data Exchange (ETDEWEB)

Dougherty, P.M.; Dafny, N.

1987-11-01

Exposure to low doses of gamma irradiation results in the modification of both the antinociceptive properties of morphine and the severity of naloxone-precipitated withdrawal in morphine-dependent rats. To better define the interactions between gamma irradiation and these opiate-mediated phenomena, dose-response studies were undertaken of the effect of irradiation on morphine-induced antinociception, and on the naloxone-precipitated withdrawal syndrome of morphine-dependent rats. In addition, electrophysiologic studies were conducted in rats after irradiation exposure and morphine treatment correlating with the behavioral studies. The observations obtained demonstrated that the antinociceptive effects of morphine as well as naloxone-precipitated withdrawal were modified in a dose-dependent manner by irradiation exposure. In addition, irradiation-induced changes in the evoked responses obtained from four different brain regions demonstrated transient alterations in both baseline and morphine-treated responses that may reflect the alterations observed in the behavioral paradigms. These results suggest that the effects of irradiation on opiate activities resulted from physiologic alterations of central endogenous opioid systems due to alterations manifested within peripheral targets.

Evaluation of artemisia mutant lines conducted from gamma irradiation treatment

International Nuclear Information System (INIS)

Ragapadmi Purnamaningsih; EG Lestari; M Syukur

2010-01-01

Cases of Malaria diseases attack in Indonesia has been increasing. Plasmodium falciparum the cause of malaria disease is now resistant to the usual medicine. One of malaria medicine which recommended by WHO is artemisinine compound extracted from Artemisia annua L plant. Low artemisinine content is one problem of Artemisia development in Indonesia. Increasing genetic variation using gamma irradiation is one alternative method to improve artemisinin content. In 2007, induce mutation had been done to artemisia seeds using gamma irradiation at dosage of 10-100 Gy. The good rooting planlet was regenerated and acclimatized in the green house, and then the seedling (M0 generation) was planted in the field at 1545 m asl. Plants derived from seeds without gamma irradiation treatment and cultured in vitro (in vitro control) were used as control. The result showed there were some morphological variations between the mutant lines (plant height, shape of the leaves and time of flowering). Ten mutant lines were selected based on biomass yield and analyzed for the artemisinine content.The result showed that artemisinine content of the mutant lines ranged from 0.44 - 1.41%, and it was significantly higher than that of in vitro control (0.43%). (author)

Optical and electrical properties of some electron and proton irradiated polymers

International Nuclear Information System (INIS)

Mishra, R.; Tripathy, S.P.; Sinha, D.; Dwivedi, K.K.; Ghosh, S.; Khathing, D.T.; Mueller, M.; Fink, D.; Chung, W.H.

2000-01-01

Ion beam treatment studies have been carried out to investigate the potential for improvements in conductivity properties of the polymers Polytetrafluroethylene (PTFE), Polyimide (PI), Polyethyleneterepthalate (PET) and Polypropylene (PP), after 2 MeV electron and 62 MeV proton irradiation. The shift in optical absorption edges as observed by UV-VIS spectra of the irradiated polymers has been correlated to the optical band-gap using Tauc's expression. A decrease in the optical band-gap has been observed in irradiated PP and PTFE, but no considerable change was found for the optical band-gaps of PET and PI. Further AC conductivity measurements confirmed an increase in conductivity in electron irradiated PP

Variation in viscosity and ion conductivity of a polymer–salt complex ...

Indian Academy of Sciences (India)

The ion conductivity shows a strong increase for an irradiation of. 35 kGy. DSC studies indicate a decrease in crystallinity with gamma dose. Keywords. Gamma irradiation; polymer electrolyte; viscosity; ion conductivity. PACS Nos 61.82.Pv; 66.30.Dn; 47.57.Ng; 81.70.Pg. 1. Introduction. When polymers are exposed to high ...

Study of the degradation process of polyimide induced by high energetic ion irradiation

International Nuclear Information System (INIS)

Severin, Daniel

2008-01-01

The dissertation focuses on the radiation hardness of Kapton under extreme radiation environment conditions. To study ion-beam induced modifications, Kapton foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (e.g. Ti, Mo, Au, and U) within a large fluence regime (1 x 10 10 -5 x 10 12 ions/cm 2 ). The irradiated Kapton foils were analysed by means of infrared and UV/Vis spectroscopy, tensile strength measurement, mass loss analysis, and dielectric relaxation spectroscopy. For testing the radiation stability of Kapton at the cryogenic operation temperature (5-10 K) of the superconducting magnets, additional irradiation experiments were performed at the Grand Accelerateur National d' Ions Lourds (GANIL, France) focusing on the online analysis of the outgassing process of small volatile degradation fragments. The investigations of the electrical properties analysed by dielectric relaxation spectroscopy exhibit a different trend: high fluence irradiations with light ions (e.g. Ti) lead to a slight increase of the conductivity, whereas heavy ions (e.g. Sm, Au) cause a drastic change already in the fluence regime of nonoverlapping tracks (5 x 10 10 ions/cm 2 ). Online analysis of the outgassing process during irradiation at cryogenic temperatures shows the release of a variety of small gaseous molecules (e.g. CO, CO 2 , and short hydro carbons). Also a small amount of large polymer fragments is identified. The results allow the following conclusions which are of special interest for the application of Kapton as insulating material in a high-energetic particle radiation environment. a) The material degradation measured with the optical spectroscopy and tensile strength tests are scalable with the dose deposited by the ions. The high correlation of the results allows the prediction of the mechanical degradation with the simple and non-destructive infrared spectroscopy. The degradation curve points to a critical material degradation which

Study of the degradation process of polyimide induced by high energetic ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Severin, Daniel

2008-09-19

The dissertation focuses on the radiation hardness of Kapton under extreme radiation environment conditions. To study ion-beam induced modifications, Kapton foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (e.g. Ti, Mo, Au, and U) within a large fluence regime (1 x 10{sup 10}-5 x 10{sup 12} ions/cm{sup 2}). The irradiated Kapton foils were analysed by means of infrared and UV/Vis spectroscopy, tensile strength measurement, mass loss analysis, and dielectric relaxation spectroscopy. For testing the radiation stability of Kapton at the cryogenic operation temperature (5-10 K) of the superconducting magnets, additional irradiation experiments were performed at the Grand Accelerateur National d' Ions Lourds (GANIL, France) focusing on the online analysis of the outgassing process of small volatile degradation fragments. The investigations of the electrical properties analysed by dielectric relaxation spectroscopy exhibit a different trend: high fluence irradiations with light ions (e.g. Ti) lead to a slight increase of the conductivity, whereas heavy ions (e.g. Sm, Au) cause a drastic change already in the fluence regime of nonoverlapping tracks (5 x 10{sup 10} ions/cm{sup 2}). Online analysis of the outgassing process during irradiation at cryogenic temperatures shows the release of a variety of small gaseous molecules (e.g. CO, CO{sub 2}, and short hydro carbons). Also a small amount of large polymer fragments is identified. The results allow the following conclusions which are of special interest for the application of Kapton as insulating material in a high-energetic particle radiation environment. a) The material degradation measured with the optical spectroscopy and tensile strength tests are scalable with the dose deposited by the ions. The high correlation of the results allows the prediction of the mechanical degradation with the simple and non-destructive infrared spectroscopy. The degradation curve points to a

Radiation-induced conductivity of doped silicon in response to photon, proton and neutron irradiation

International Nuclear Information System (INIS)

Kishimoto, N.; Amekura, H.; Plaksin, O.A.; Stepanov, V.A.

2000-01-01

The opto-electronic performance of semiconductors during reactor operation is restricted by radiation-induced conductivity (RIC) and the synergistic effects of neutrons/ions and photons. The RICs of Si due to photons, protons and pulsed neutrons have been evaluated, aiming at radiation correlation. Protons of 17 MeV with an ionizing dose rate of 10 3 Gy/s and/or photons (hν=1.3 eV) were used to irradiate impurity-doped Si (2x10 16 B atoms/cm 3 ) at 300 and 200 K. Proton-induced RIC (p-RIC) and photoconductivity (PC) were intermittently detected in an accelerator device. Neutron-induced RIC (n-RIC) was measured for the same Si in a pulsed fast-fission reactor, BARS-6, with a 70-μs pulse of 2x10 12 n/cm 2 (E>0.01 MeV) and a dose rate of up to 6x10 5 Gy/s. The neutron irradiation showed a saturation tendency in the flux dependence at 300 K due to the strong electronic excitation. Normalization of the electronic excitation, including the pulsed regime, gave a fair agreement among the different radiation environments. Detailed comparison among PC, p-RIC and n-RIC is discussed in terms of radiation correlation including the in-pile condition

Flux and energy deposition distribution studies inside the irradiation room of the portuguese 60Co irradiation facility

International Nuclear Information System (INIS)

Portugal, Luis; Oliveira, Carlos

2008-01-01

Full text: In December 2003 the irradiator of the Portuguese 60 Co irradiation facility, UTR, was replenished. Eighteen new sources were loaded and the older ones (156) were rearranged. The result was an irradiator with about 10.2 P Bq of total activity. The active area of the irradiator has also increased. Now it uses twenty five of the thirty tubes of the source rack, nine more than in the previous geometry. This facility was designed mainly for sterilisation of medical devices. However it is also used for the irradiation of other products such as cork stoppers, plastics and a limited number of food and feed. The purpose of this work is to perform dosimetric studies inside the irradiation room of a 60 Co irradiation facility, particularly, the flux and energy deposition distributions. The MCNPX code was used for the simulation of the facility. The track average mesh tally capabilities of MCNPX were used to plot the photon flux and energy deposition distributions. This tool provides a fast way for flux and energy deposition mapping. The absorbed dose distribution near the walls of the irradiation room was also calculated. Instead of using meshtallys as before, the average absorbed dose inside boxes lined with the walls was determined and afterwards a plot of its distribution was made. The absorbed dose rates obtained ranged from 5 to 500 Gy.h -1 depending on material being irradiated in process and the location on the wall. These positions can be useful for fixed irradiation purposes. Both dosimetric studies were done considering two different materials being irradiated in the process: cork stoppers and water, materials with quite different densities (0.102 and 1 g.cm-3, respectively). These studies showed some important characteristics of the radiation fields inside the irradiation room, namely its spatial heterogeneity. Tunnelling and shadow effects were enhanced when the product boxes increases its density. Besides a deeper dosimetric understanding of the

A recommendation for the thermal conductivity of oxide fuels

International Nuclear Information System (INIS)

Kang, K. H.; Ryu, H. J.; Song, K. C.; Yang, M. S.; Na, S. H.; Lee, Y. W.; Moon, H. S.; Kim, H. S.

2004-01-01

The thermal conductivity of nuclear fuel is one of the most important properties because it affects the fuel operating temperature. Therefore, it influences almost all the important processes occurred in nuclear fuel during irradiation, such as gas release, swelling and grain growth. The model of the thermal conductivity of nuclear fuel should be used in the codes to evaluate the performance of it analytically and be required in the nuclear fuel research and development. The thermal conductivity, k, of UO 2 depends on the deviation from stoichiometry, x, the burnup, b, and the fractional porosity, p, as well as the temperature, T: k = k(x, b, p, T), (1) Changes in thermal conductivity occur during irradiation because of fission-gas bubble formation, pores, cracks, fission product build-up and possible changes in the oxygen to uranium ratio (O/U). The dependence on temperature and porosity has been well studied and incorporated in computer codes used for the in-pile fuel behavior analysis. There are several studies on the effect of impurity on the thermal conductivity of UO 2 . In this paper, the variables affected on the thermal conductivity were studied. The available data of the thermal conductivity of UO 2 , UO 2+x , (U, Pu)O 2 , (U, Pu)O 2 and simulated fuel for irradiation fuel were reviewed and analyzed. The best models were recommended

Cost/benefit study on date disinfestation by gamma irradiation in Algeria

International Nuclear Information System (INIS)

Mahlous, M.

2002-01-01

To establish the irradiation technology, one must have a holistic approach to the technology of food irradiation in order to assure a maximum utilization rate of the facility. The assumptions in this study are based on a free standing multipurpose irradiation facility, the throughput of which is expressed in t·kGy/year, and the unit cost of the treatment in US $/t·kGy. These values may then be applied for the calculation of the treatment cost of any food commodity, according to the irradiation dose needed. The study showed that irradiation treatment of dates is profitable and that the cost of irradiation does not exceed 1.6% of the selling price of the product. Post harvest losses may be considerably reduced thanks to irradiation treatment. A comparative study between irradiation and cold storage showed that irradiation will cost 30% less than cold storage. This study is completed by an evaluation of consumer acceptance of irradiated food products. (author)

Irradiation effects on transport properties of polyaniline and polyaniline/bentonite composite

Energy Technology Data Exchange (ETDEWEB)

Tilki, T., E-mail: tahirtilki@sdu.edu.tr [Suleyman Demirel University, Faculty of Arts and Sciences, Department of Chemistry, 32260 Isparta (Turkey); Karabulut, O. [Pamukkale University, Faculty of Arts and Sciences, Department of Physics, Denizli (Turkey); Yavuz, M. [Suleyman Demirel University, Faculty of Arts and Sciences, Department of Chemistry, 32260 Isparta (Turkey); Kaplan, A. [Suleyman Demirel University, Faculty of Arts and Sciences, Department of Physics, Isparta (Turkey); Cabuk, M. [Suleyman Demirel University, Faculty of Arts and Sciences, Department of Chemistry, 32260 Isparta (Turkey); Mus Alparslan University, Faculty of Arts and Sciences, Department of Chemistry, Mus (Turkey); Takanoglu, D. [Pamukkale University, Faculty of Arts and Sciences, Department of Physics, Denizli (Turkey)

2012-08-15

In this study, the effects of irradiation on pure polyaniline and polyaniline/bentonite composites synthesized chemically were investigated by means of thermogravimetric measurements, UV, SEM, XRD, absorption and temperature dependent electrical conductivity in the temperature range of 85-400 K. The irradiation process was carried out in air in a conventional gamma chamber, which uses a {sup 60}Co source and the samples were exposed to dose 40 kGy. The initial decomposition and first degradation temperatures of PAni/Bnt and Irradiated PAni/Bnt composites obtained from thermogravimetric measurements were higher than those of PAni and irradiated PAni. This could have been caused by the treatment with bentonite during aniline polymerization. The XRD patterns revealed that the peak positions of the as-prepared and irradiated samples were the same but the intensities of the peaks decreased with irradiation due to breaking of the polymer chain, which induces more amorphous regions in the polymer structure. It was found from temperature dependent conductivity measurements that the radiation significantly influenced the conductivity of PAni and PAni/Bnt composites. The conductivity results show that the dominant conduction mechanisms were hopping for all samples due to wide range of localized states present near the Fermi level. -- Highlights: Black-Right-Pointing-Pointer The effects of irradiation on PAni and PAni/Bnt composites were investigated. Black-Right-Pointing-Pointer We observed that irradiation increases the homogeneity of the samples. Black-Right-Pointing-Pointer The band edge is shifted toward lower photon energies in the irradiated samples. Black-Right-Pointing-Pointer The conductivity of PAni and PAni/Bnt composites were changed by the irradiation. Black-Right-Pointing-Pointer The dominant conduction mechanism was found to be Mott's variable range hopping.

Fuel irradiation experience at Halden

International Nuclear Information System (INIS)

Vitanza, Carlo

1996-01-01

The OECD Halden Reactor Project is an international organisation devoted to improved safety and reliability of nuclear power station through an user-oriented experimental programme. A significant part of this programme consists of studies addressing fuel performance issues in a range of conditions realised in specialised irradiation. The key element of the irradiation carried out in the Halden reactor is the ability to monitor fuel performance parameters by means of in-pile instrumentation. The paper reviews some of the irradiation rigs and the related instrumentation and provides examples of experimental results on selected fuel performance items. In particular, current irradiation conducted on high/very high burn-up fuels are reviewed in some detail

Study on determination method of identifying irradiated chicken

International Nuclear Information System (INIS)

Guo Liping; Yu Xuejun; Yu Menghong; Fu Junjie; Zhang Shimin; Bao Jinsong

2003-01-01

The effects of gamma irradiation on the activities of aleipsis, peroxidase, perhydrol catalase and the peroxide values in chicken oil and effects of different storage time on self-oxidation of fat and lipa in irradiated chicken were studied. The results showed that the activities of aleipsis and perhydrol catalase in irradiated chicken decreased with increasing doses, and the peroxide activity and peroxide value of lipa increased with increase of doses. No significant effect of storage time on peroxide value was observed in the irradiated chicken

Some wholesomeness studies on irradiated Iraqi dates

International Nuclear Information System (INIS)

Al Rawi, A.M.; Hamoudi, H.I.

1981-01-01

Iraqi dates (Zahdi and Khestawi) were irradiated at different dose levels (0 to 1500 krad) to extend their shelf-lives. Samples irradiated at 150 krad showed no change in the behaviour studies of tested Swiss albino mice. Fungi were found to have a constant rate of growth on the syrup irradiated dates. Chemical products such as malondialdehyde, deoxy sugars, acids and reducing sugars were quantified. In conclusion, 150 krad is a convenient dose to extend the shelf-lives of the tested dates and is therefore recommended. (author)

[Alaskan commodities irradiation project: An options analysis study

International Nuclear Information System (INIS)

Zarling, J.P.; Swanson, R.B.; Logan, R.R.

1989-09-01

The ninety-ninth US Congress commissioned a six-state food irradiation research and development program to evaluate the commercial potential of this technology. Hawaii, Washington, Iowa, Oklahoma and Florida as well as Alaska have participated in the national program; various food products including fishery products, red meats, tropical and citrus fruits and vegetables have been studied. The purpose of the Alaskan study was to review and evaluate those factors related to the technical and economic feasibility of an irradiator in Alaska. This options analysis study will serve as a basis for determining the state's further involvement in the development of food irradiation technology

Study on silk yellowing induced by gamma-irradiation

International Nuclear Information System (INIS)

Tsukada, Masuhiro; Aoki, Akira

1985-01-01

The changes in the yellow color of silk threads with total dose of irradiation applied were described and studied by a colorimetric method and by monochrome photography. The change into a yellow color of the specimen in the course of irradiation was clearly detected in photographs using filters, 2B and SC 56 under light conditions at the wavelength of 366 nm. The b/L value measured by colorimetry in undegummed and degummed silk fibers sharply increased in the early stage of irradiation. Yellow color indices (b/L) of the specimen subjected to gamma-irradiation continued to increase and the yellow color of the silk threads became more pronounced above a total dose of irradiation of 21 Mrad. The b/L value of the undegummed silk fiber which had deen irradiated was about 2 times that of the degummed silk fiber. (author)

Irradiation effect study on dynamic performance of grease

International Nuclear Information System (INIS)

Arakawa, Kazuo; Sasuga, Tsuneo; Hagiwara, Miyuki; Yajima, Toshio; Nakanishi, Hiroshi; Soda, Takao; Iwamoto, Takeshi.

1986-03-01

The radiation resistance of newly developed grease, MORESCO HIRAD RG-42-0, consisting of polyphenyl ether as base oil and inorganic compound as gelling agent was evaluated by conducting measurements of frictional resistance force on mechanical snubbers. After the irradiation of 60 Co γ-rays up to a predetermined dose [max. 100 MGy (10000 Mrad)], the grease was applied to mechanical snubbers. The rated load of mechanical snubbers used (standard stroke of 125 mm) was set at 0.16 ton and 1.0 ton. The frictional resistance force was measured at a velocity of 0.001, 0.01, 0.1 and 2.0 mm/sec and at temperature of 60 deg C. When the rated load was 0.16 ton, the frictional resistance force of irradiated grease was kept less than a criterion, a greater value of either 5 kgf or 1 % of the rated load, at every tested dose up to 90 MGy. In case of 1.0 ton, the frictional resistance force of the irradiated grease was less than a greater value of either 10 kgf or 1 % of the rated load at doses up to 70 MGy. (author)

Improvement of Electrical Conductivity of Single-Walled Carbon Nano tube Network Using Particle Irradiation

International Nuclear Information System (INIS)

Lim, Suntaek; Kim, Gonho

2010-01-01

Substitution for Indium Tin Oxide of transparent electrode Applications : Flat panel displays, Touch panel, Solar cell, EM wave shielding... For very low energy of 20 eV and 90 eV, argon ion irradiations, the surface of SWCNT bundles were sputtered and thinned the diameter of the bundle. With increasing the incident ion energy as 7.5 keV, SWCNT bundles were networked by amorphization of cross welded CNTs. → Less damage can be obtained from higher energy of irradiated particle due to less collision cross section. For 10 MeV proton and 800 keV electron irradiations, there are no severe damages. Electron irradiation is more effective on network with less damage than that of ion irradiation. → Network process can be proceeded with the generation of free carbon, the migration of free carbon on CNT and reconstruction of the cross linked CNTs, which processes require the latent energy on CNT body after collision. It can be controlled by the energy and dose of irradiation particle

Protective effects of y-irradiation to streptozotocin induced diabetic rats: A biochemical and histological study

International Nuclear Information System (INIS)

Gharib, O.A.; Noman, E.; Abo-Nour, S.

2007-01-01

The present study was conducted to evaluate the possible protective effect of low dose of gamma radiation against pancreatic cells damage in streptozotocin (STZ) diabetic rats. Young male Wister rats were divided into the control group, the irradiated groups, which divided into two subgroups, single irradiated group, which subjected to 0.5 Gy of whole body gamma-irradiation as a single dose and repeated irradiated group, which subjected to 0.5 Gy of whole body gamma-irradiation as a repeated dose (0.5 Gy daily for two days). The 3 r d groups, which in turn subdivided into three subgroups, STZ group administrated to a single dose of 45 mg kg -1 of STZ (i.p), the STZ single irradiated group, subjected to single irradiated dose after the STZ administration and STZ repeated irradiated group, that exposed to repeated dose of radiation after the STZ administration. The diabetic rats presented a significant increase in plasma glucose and lipid peroxidation and a significant decrease in both whole blood SOD and GSH as well as in liver tissue. In addition, marked depression was observed in plasma and liver glutathione- S-transferase compared with normal rats. Low dose of radiation as a single or repeated doses, significantly reduced blood glucose and TEARS and significantly increased SOD activity and GSH content in both blood and liver besides a marked amelioration in GST activity in plasma and liver tissues. The ultra structural studies revealed that STZ affects both cells of pancreas. There was a reduction in secretary granules and rough endoplasmic reticulum with the accumulation of lipid. Low dose of y-rays exposure result a remarkable protective effect on biochemical and histological level

The influence of Ga{sup +} irradiation on the transport properties of mesoscopic conducting thin films

Energy Technology Data Exchange (ETDEWEB)

Barzola-Quiquia, J; Dusari, S; Bridoux, G; Bern, F; Molle, A; Esquinazi, P, E-mail: j.barzola@physik.uni-leipzig.de, E-mail: esquin@physik.uni-leipzig.de [Division of Superconductivity and Magnetism, Universitaet Leipzig, Linnestrasse 5, D-04103 Leipzig (Germany)

2010-04-09

We studied the influence of 30 keV Ga{sup +}-ions-commonly used in focused-ion-beam (FIB) devices-on the transport properties of thin crystalline graphite flakes, and La{sub 0.7}Ca{sub 0.3}MnO{sub 3} and Co thin films. The changes in electrical resistance were measured in situ during irradiation and also the temperature and magnetic field dependence before and after irradiation. Our results show that the transport properties of these materials strongly change at Ga{sup +} fluences much below those used for patterning and ion-beam-induced deposition (IBID), seriously limiting the use of FIB when the intrinsic properties of the materials of interest are of importance. We present a method that can be used to protect the sample as well as to produce selectively irradiation-induced changes.

Electron spin resonance studies of some irradiated pharmaceuticals

International Nuclear Information System (INIS)

Gibella, M.; Crucq, A-S.; Tilquin, B.; Stocker, P.; Lesgards, G.; Raffi, J.

2000-01-01

Five antibiotics belonging to the cephalosporins and penicillins groups have been irradiated: anhydrous ampicilline acid, amoxicilline acid trihydrate, cefuroxime sodium salt, cloxacilline sodium salt monohydrate and ceftazidime pentahydrate. ESR studies have been carried out, showing the influence of irradiation and storage parameters on the nature and concentration of the free radicals trapped. These results may be used to detect an irradiation treatment on such pharmaceuticals. (author)

Pristine and γ-irradiated halloysite reinforced epoxy nanocomposites - Insight study

Science.gov (United States)

Saif, Muhammad Jawwad; Naveed, Muhammad; Zia, Khalid Mahmood; Asif, Muhammad

2016-10-01

The present study focuses on development of epoxy system reinforced with naturally occurring halloysite nanotubes (HNTs). A comparative study is presented describing the performance of pristine and γ-irradiated HNTs in an epoxy matrix. The γ-irradiation treatment was used for structural modification of natural pristine HNTs under air sealed environment at different absorbed doses and subsequently these irradiated HNTs were incorporated in epoxy resin with various wt% loadings. The consequences of γ-irradiation on HNTs were studied by FTIR and X-ray diffraction analysis (XRD) in terms of changes in functional groups and crystalline characteristics. An improvement is observed in mechanical properties and crack resistance of composites reinforced with γ-irradiated HNTs. The irradiated HNTs imparted an improved flexural and tensile strength/modulus along with better thermal performance.

Study on biologically active substances in irradiated apple juice

International Nuclear Information System (INIS)

Tencheva, S.

1975-01-01

The radiochemical changes proceeding by irradiation of foodstuffs rich in carbohydrates are studied. For the purpose pure solutions of D-glucose, D-fructose and sucrose and fresh apple juice, irradiated with 0,5 and 1,0 Mrad are investigated. Changes set in UV-spectra of the irradiated foodstuffs, the specific reaction of malonic dialdehyde formation with 2-thiobarbituric acid and the formation of carbonyl compounds reacting with 2,4-dinitro phenylhydrazine are studied. Results show that in the irradiated sample solutions of sugars and apple juice two peaks are formed. The malonic dialdehyde formation depends on the dose of irradiation applied. The newly formed carbonyl compounds both in the sample solutions and in the juice are 8 to 9 in number. (author)

Water-assisted and thermally-enhanced protonic conduction in HZSM-5, effect of gamma-irradiation on the electric properties. [Zeolites

Energy Technology Data Exchange (ETDEWEB)

Higazy, A.A.; Kassem, M.E. (Qatar Univ. (Qatar). Physics Dept.); Sayed, M.B. (Qatar Univ. (Qatar). Chemistry Dept.)

1992-01-01

Analysis of the a.c. conductivity of the zeolite HZSM-5, in the 0.1-100 kHz frequency region and the 300-700 K temperature range, reveals semiconducting features based predominantly on an ionic mechanism. This is reflected in a low-frequency Cole-Cole dependence of the Z''(Z') impedance and in a linear dependence of the {epsilon}''(''epsilon''') dielectric constant throughout the temperature range. The zeolite Broensted sites are the active centers responsible for the ionic conduction. As the conductivity drops to 373 K, sorbed water seems to participate in the conduction as a vehicle assisting the proton mobility. Above 373 K, the conductivity continues to rise as an indication of critical transition into a thermally enhanced ionic conduction. Both low-temperature sorbed water and high-temperature thermal motion are necessary to ensure a firm contact at the aggregate surfaces, where conduction takes place. Gamma-irradiation also participates in the conduction by creating new sites sensitive to the same parameters governing the conduction mechanism. (author).

Study on ceramic breeder and related materials by means of work function measurement under irradiation

International Nuclear Information System (INIS)

Luo, G.N.; Terai, T.; Yamawaki, M.; Yamaguchi, K.

2002-01-01

Ceramic breeder materials, Li 2 O, LiAlO 2 and Li 4 SiO 4 , under irradiation have been studied using a Kelvin probe that measures work function changes of materials. Surface charging was observed to influence greatly the probe output, which can be explained qualitatively employing a model concerning induction electric field due to external field and free charges on ceramic surface. It is found that the insulating ceramics could not be studied properly with the Kelvin probe. A probable solution is to heat the ceramics, so as to raise their electric conductivities high enough to root out the surface charging. Also briefly discussed is the application of the probe to metals under ion irradiation. (orig.)

Physiological and Biophysical Studies on Gamma Irradiated Rat Treated with Dehydroepiandrosterone Sulfate (DHEAS)

International Nuclear Information System (INIS)

Hamza, G.R.A.

2015-01-01

Dehydroepiandrosterone Sulfate (DHEAS) is an adrenal hormone, and is the most abundant circulatory steroid hormone in the body. Serum DHEAS concentration peaks at around age 25 years, displaying a significant decrease with age linked with some pathological changes. Objective: This study was performed to investigate the effect(s) of DHEAS oral administration, and its possible prophylactic and/or mitigating roles against γ-irradiation-induced disorders in the irradiated rat. Experimental Animals and Design: Five groups of male Albino rats were used: 1- Control: untreated group. 2- Irradiated: animals exposed to a single dose of whole-body γ-irradiation (6 Gy). 3- DHEAS group: given a single dose of DHEAS (20 mg/100 g b. wt.), intra gastrically. 4-DHEAS + Irrad. group: given a single dose of DHEAS, 2 hrs before irradiation. 5- Irrad.+ DHEAS group: given DHEAS, 2 hrs after irradiation. Blood and testicular tissue samples were collected after one day, one week and two weeks post irradiation or DHEAS treatment. Parameters Measured: Plasma levels of triiodothyronine (T 3 ), thyroxin (T 4 ), thyrotropin (TSH), testosterone, acid phosphatase (ACP), triglycerides (TG), total cholesterol, high density lipoprotein-cholesterol (HDL-Ch), low density lipoprotein-cholesterol (LDL-Ch) were determined, and the atherogenic index (AI) was calculated. Reduced glutathione (GSH) content and malondialdehyde (MDA) levels were measured in blood and testes. A complete blood picture and some biophysical properties were also examined. Results: DHEAS administration pre-irradiation, and to a lesser magnitude, post-irradiation, improved the disturbances induced by irradiation in the plasma levels of the tested parameters: tT 3 , tT 4 , and TSH, testosterone and the lipid profile, showing almost normalization of the AI. Beneficial effects were also observed in the hematological picture, blood viscosity and conductivity. DHEAS elevated GSH levels and decreased lipid peroxidation (LPO) in blood

Physiological Studies On Response Of Grape Transplants To Mineral And Irradiated Organic Fertilizers

International Nuclear Information System (INIS)

Mohamed, M.F.A.

2013-01-01

This work was conducted during two successive seasons throughout 2008, 2009 and 2010 years under green house conditions. Three factorial experiments were included the 1st was dealing with investigating the effect of soil added compost rate (0.0, 5.0, 10.0 and 20.0 %) and gamma irradiated compost dose (0.0, 5.0, 10.0 and 15.0 KGy). Where, two other experiments were devoted for studying the effect of soil applied compost (irradiated or un-irradiated) from one hand and the rate of either N (urea/ ammonium sulphate) or K (K 2 SO 4 ) fertilization rates from the other for 2nd and 3rd experiments, respectively. Obtained results could be summarized as follows: 1- Application of compost, in particular irradiated one at 10.0% was the most promising treatment in the 1st experiment, improved significantly all growth, leaf chlorophyll, stem total carbohydrates and leaf mineral composition especially macro elements (N, P and K). 2- All N or K soil applied reflected positively on the above mentioned measurements of Thompson seedless rooted cuttings with a relative tendency of variance occurred from one N or K treatment to another. 3- It can be concluded that compost application to coarse-textured soil improved it and reflected on plants. Irradiating compost with effective dose (10 KGy) greatly increased compost efficiency which could be reached the double.

Study of boron carbide evolution under neutron irradiation

International Nuclear Information System (INIS)

Simeone, D.

1999-01-01

Owing to its high neutron efficiency, boron carbide (B 4 C) is used as a neutron absorber in control rods of nuclear plants. Its behaviour under irradiation has been extensively studied for many years. It now seems clear that brittleness of the material induced by the 10 B(n,α) 7 Li capture reaction is due to penny shaped helium bubbles associated to a high strain field around them. However, no model explains the behaviour of the material under neutron irradiation. In order to build such a model, this work uses different techniques: nuclear microprobe X-ray diffraction profile analysis and Raman and Nuclear Magnetic Resonance Spectroscopy to present an evolution model of B 4 C under neutron irradiation. The use of nuclear reactions produced by a nuclear microprobe such as the 7 Li(p,p'γ) 7 Li reaction, allows to measure lithium profile in B 4 C pellets irradiated either in Pressurised Water Reactors or in Fast Breeder Reactors. Examining such profiles enables us to describe the migration of lithium atoms out of B 4 C materials under neutron irradiation. The analysis of X-ray diffraction profiles of irradiated B 4 C samples allows us to quantify the concentrations of helium bubbles as well as the strain fields around such bubbles.Furthermore Raman spectroscopy studies of different B 4 C samples lead us to propose that under neutron irradiation. the CBC linear chain disappears. Such a vanishing of this CBC chain. validated by NMR analysis, may explain the penny shaped of helium bubbles inside irradiated B 4 C. (author)

Study of irradiation damage structures in austenitic stainless steels

Energy Technology Data Exchange (ETDEWEB)

Hamada, Shozo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-08-01

The irradiation damage microstructures in austenitic stainless steels, which have been proposed to be a candidate of structural materials of a fusion reactor, under ions and neutrons irradiation have been studied. In ion irradiation experiments, cross-sectional observation of the depth distribution of damage formed due to ion irradiation became available. Comparison and discussion between experimental results with TEM and the calculated ones in the depth profiles of irradiation damage microstructures. Further, dual-phase stainless steels, consisted of ferritic/austenitic phases, showed irradiation-induced/enhanced precipitation during ion irradiation. High Flux Isotope Reactor with high neutron fluxes was employed in neutron-irradiation experiments. Swelling of 316 steel showed irradiation temperature dependence and this had strong correlation with phase instability under heavy damage level. Swelling resistance of Ti-modified austenitic stainless steel, which has good swelling resistance, decreased during high damage level. This might be caused by the instability of Ti-carbide particles. The preparation method to reduce higher radioactivity of neutron-irradiated TEM specimen was developed. (author). 176 refs.

Study of irradiation damage structures in austenitic stainless steels

International Nuclear Information System (INIS)

Hamada, Shozo

1997-08-01

The irradiation damage microstructures in austenitic stainless steels, which have been proposed to be a candidate of structural materials of a fusion reactor, under ions and neutrons irradiation have been studied. In ion irradiation experiments, cross-sectional observation of the depth distribution of damage formed due to ion irradiation became available. Comparison and discussion between experimental results with TEM and the calculated ones in the depth profiles of irradiation damage microstructures. Further, dual-phase stainless steels, consisted of ferritic/austenitic phases, showed irradiation-induced/enhanced precipitation during ion irradiation. High Flux Isotope Reactor with high neutron fluxes was employed in neutron-irradiation experiments. Swelling of 316 steel showed irradiation temperature dependence and this had strong correlation with phase instability under heavy damage level. Swelling resistance of Ti-modified austenitic stainless steel, which has good swelling resistance, decreased during high damage level. This might be caused by the instability of Ti-carbide particles. The preparation method to reduce higher radioactivity of neutron-irradiated TEM specimen was developed. (author). 176 refs

Charge deep-level transient spectroscopy study of high-energy-electron-beam-irradiated hydrogenated amorphous silicon

NARCIS (Netherlands)

Klaver, A.; Nádaždy, V.; Zeman, M.; Swaaiij, R.A.C.M.M.

2006-01-01

We present a study of changes in the defect density of states in hydrogenated amorphous silicon (a-Si:H) due to high-energy electron irradiation using charged deep-level transient spectroscopy. It was found that defect states near the conduction band were removed, while in other band gap regions the

Microbiological studies of irradiated dried mackerel (Cybium guttatum Bloch and Schnieder)

International Nuclear Information System (INIS)

Ahmed, M.; Joardar, S.K.; Bhuiya, A.D.; Islam, M.S.

1985-01-01

Microbiological studies of sun-dried mackerel fish, Cybium guttatum, were conducted by exposing the fish to doses of gamma-rays from 0.50 to 8.00 kGy at the storage temperatures of 10.20 and 30oC. The reduction of bacterial flora was determined both qualitatively and quantitatively. At 4 kGyone log cycle reduction of bacterial flora was achieved and at 8 kGy the reduction was nearly 2 log cycles. The irradiated samples were stored for two months and viable bacterial counts were taken. Except in a few cases, reduction in viable counts occurred. Bacterial isolates were made and both Mesophiles and Psychrophiles were identified. Micrococcus, Staphylococcus, Corymebacterium and some Bacillus were found to be the prominent groups in mesophiles, while Bacillus dominated in psychrophiles. Staphylococcus was found to be the most dominant bacterial flora in unirradiated samples, but they were highly affected by irradiation

Feeding Studies of Irradiated Foods with Insects

Energy Technology Data Exchange (ETDEWEB)

Loaharanu, Srisan

1978-06-15

Insects are of value to man in many scientific studies. Microsomal detoxication systems exist in both insects and mammals. In the preliminary investigations it was found that irradiated cocoa beans and white and red kidney beans (Phaseolus spp.) did not significantly change the percentage of egg-hatch in the insects tested. In more detailed investigations food samples that are susceptible to insect spoilage and are representatives of widely consumed human foods were fed to various insect species. The development, sex distortion and reproductivity of the insects were investigated. Cytogenetic aberrations as related to dominant lethality were studied in insects with reasonably clear chromosomal patterns. The meiosis stage was examined, using the squash technique and Aceto-orcein staining. Black beans, Phaseolus spp., irradiated with up to 200 krad of gamma rays did not apparently change the percentage of survival and the sex ratio of the bean weevil, Zabrotes subfasciatus. Dominant lethality in the German cockroach, Blatella germanica, fed on irradiated black beans did not apparently occur when considering the results of cytological investigation and the number of offspring obtained. Dried sardine samples irradiated with up to 400 krad of gamma rays neither apparently affected the survival nor caused sex distortion in the cheese skipper, Piophila casei. This irradiated product apparently did not induce dominant lethality in the German cockroach as tested. Coffee processed from coffee beans that had been irradiated with up to 100 krad of gamma rays did not apparently cause adverse effects on the experimental insects. (author)

Feeding studies of irradiated foods with insects

International Nuclear Information System (INIS)

Loaharanu, S.

1978-01-01

Insects are of value to man in many scientific studies. Microsomal detoxication systems exist in both insects and mammals. In the preliminary investigations it was found that irradiated cocoa beans and white and red kidney beans (Phaseolus spp.) did not significantly change the percentage of egg-hatch in the insects tested. In more detailed investigations food samples that are susceptible to insect spoilage and are representatives of widely consumed human foods were fed to various insect species. The development, sex distortion and reproductivity of the insects were investigated. Cytogenetic aberrations as related to dominant lethality were studied in insects with reasonably clear chromosomal patterns. The meiosis stage was examined, using the squash technique and Aceto-orcein staining. Black beans, Phaseolus spp., irradiated with up to 200 krad of gamma rays did not apparently change the percentage of survival and the sex ratio of the bean weevil, Zabrotes subfasciatus. Dominant lethality in the German cockroach, Blatella germanica, fed on irradiated black beans did not apparently occur when considering the results of cytological investigation and the number of offspring obtained. Dried sardine samples irradiated with up to 400 krad of gamma rays neither apparently affected the survival nor caused sex distortion in the cheese skipper, Piophila casei. This irradiated product apparently did not induce dominant lethality in the German cockroach as tested. Coffee processed from coffee beans that had been irradiated with up to 100 krad of gamma rays did not apparently cause adverse effects on the experimental insects. (author)

Pristine and γ-irradiated halloysite reinforced epoxy nanocomposites – Insight study

International Nuclear Information System (INIS)

Saif, Muhammad Jawwad; Naveed, Muhammad; Zia, Khalid Mahmood; Asif, Muhammad

2016-01-01

The present study focuses on development of epoxy system reinforced with naturally occurring halloysite nanotubes (HNTs). A comparative study is presented describing the performance of pristine and γ-irradiated HNTs in an epoxy matrix. The γ-irradiation treatment was used for structural modification of natural pristine HNTs under air sealed environment at different absorbed doses and subsequently these irradiated HNTs were incorporated in epoxy resin with various wt% loadings. The consequences of γ-irradiation on HNTs were studied by FTIR and X-ray diffraction analysis (XRD) in terms of changes in functional groups and crystalline characteristics. An improvement is observed in mechanical properties and crack resistance of composites reinforced with γ-irradiated HNTs. The irradiated HNTs imparted an improved flexural and tensile strength/modulus along with better thermal performance. - Highlights: • The γ-irradiation was used for structural modification of halloysite nanotubes. • Composite materials with irradiated HNTs showed improved mechanical properties. • The γ-irradiation treatment is a promising surface modification method.

Measurement of AC electrical conductivity of single crystal Al2O3 during spallation-neutron irradiation

International Nuclear Information System (INIS)

Kennedy, J.C. III; Farnum, E.H.; Sommer, W.F.; Clinard, F.W. Jr.

1993-01-01

Samples of single crystal Al 2 O 3 , commonly known as sapphire, and polycrystalline Al 2 O 3 were irradiated with spallation neutrons at the Los Alamos Spallation Radiation Effects Facility (LASREF) under various temperature conditions and with a continuously applied alternating electric field. This paper describes the results of measurements on the sapphire samples. Neutron fluence and flux values are estimated values pending recovery and analysis of dosimetry packages. The conductivity increased approximately with the square root of the neutron flux at fluences less than 3 x 10 21 n/m 2 . The increase in conductivity reached saturated levels as high as 2 x 10 -2 (ohm-m) -1 at fluences as low as 2 x 10 22 n/m 2 . Frequency swept impedance measurements indicated a change in the electrical properties from capacitive to resistive behavior with increasing fluence

Development status of irradiation devices and instrumentation for material and nuclear fuel irradiation tests in HANARO

Energy Technology Data Exchange (ETDEWEB)

Kim, Bong Goo; Sohn, Jae Min; Choo, Kee Nam [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2010-04-15

The High flux Advanced Neutron Application ReactOr (HANARO), an open-tank-in-pool type reactor, is one of the multi-purpose research reactors in the world. Since the commencement of HANARO's operations in 1995, a significant number of experimental facilities have been developed and installed at HANARO, and continued efforts to develop more facilities are in progress. Owing to the stable operation of the reactor and its frequent utilization, more experimental facilities are being continuously added to satisfy various fields of study and diverse applications. The irradiation testing equipment for nuclear fuels and materials at HANARO can be classified into capsules and the Fuel Test Loop (FTL). Capsules for irradiation tests of nuclear fuels in HANARO have been developed for use under the dry conditions of the coolant and materials at HANARO and are now successfully utilized to perform irradiation tests. The FTL can be used to conduct irradiation testing of a nuclear fuel under the operating conditions of commercial nuclear power plants. During irradiation tests conducted using these capsules in HANARO, instruments such as the thermocouple, Linear Variable Differential Transformer (LVDT), small heater, Fluence Monitor (F/M) and Self-Powered Neutron Detector (SPND) are used to measure various characteristics of the nuclear fuel and irradiated material. This paper describes not only the status of HANARO and the status and perspective of irradiation devices and instrumentation for carrying out nuclear fuel and material tests in HANARO but also some results from instrumentation during irradiation tests

Onion irradiation - a case study

International Nuclear Information System (INIS)

Huebner, G.

1988-01-01

The irradiation of onions (Allium cepa L.) serves to prevent sprouting associated with long-term storage or transport and storage of onions in climatic conditions which stimulate sprouting. JECFI the Joint Expert Committee for Food Irradiation of FAO/IAEA/WHO, recommended the application of an irradiation dose of up to 150 Gy for sprout inhibition with onions. (author)

Study of Irradiation Effects on the Fracture Properties of A533-Series Ferritic Steels

International Nuclear Information System (INIS)

Lee, Yong Bok; Lee, Gyeong Geun; Kwon, Jun Hyun

2011-01-01

Since the Kori nuclear power plant unit 3 (Kori-3) was founded in 1986, the surveillance tests have been conducted five times. One of the primary objectives of the surveillance test is to determine the effects of irradiation on reactor pressure vessel (RPV) steel embrittlement. The RPV is made out of ferritic steels such as SA533 type B class 1, which were used for early nuclear power plants industry including Kori-2, 3, 4 and Yonggwang-1, 2 units in Korea. The Westinghouse supplied Kori-3 with the RPV steels ASTM A533 grade B class 1, which is equivalent to SA533 type B class 1. The irradiation effects on tensile properties in ASTM A533 grade B class 1 steel had been studied by Steichen and Williams. They experimentally determined the effect of strain rate and temperature on the tensile properties of unirradiated and irradiated A533 grade B steel 1. The effects of neutron irradiation on ferritic steels could be determined from tensile properties, as well as the fracture strength and toughness measurements. Hunter and Williams have reported that the strength and ductility for unirradiated material at a low strain rate increase with decreasing test temperature. Also, neutron irradiation increases strength and decreases ductility. Crosley and Ripling revealed that the yield strength of unirradiated material rapidly increases with the strain rate. Therefore, yield strength for unirradiated and irradiated materials should be determined by test parameters along with strain rate and temperature. In this study we compare ASTM A533 grad B class 1 steel obtained from several papers with SA533 type B class 1 steel taken from the surveillance data of Kori-3 unit, whose mechanical property of unirradiated and irradiated materials was correlated with the rate-temperature parameter

Electrochemical methods for identification of irradiated liquid foods

International Nuclear Information System (INIS)

Xie Zongchuan; Ma Li; Shi Shuangping

1988-01-01

Samples of 14 kinds of wine, soy, vinegar, spirits, fruits in syrup, etc.were exposed to a Co-60 source. They responded with changes in electric potential and conductance. Especially, the electric potential in irradiated Shugan white spirits (made of sweet potato) was five times that in non-irradiated ones. Eighty five days after irradiation, the electric potential in the irradiated spirits dropped, but was still three times that in non- irradiated ones. The conductance in irradiated spirits was twenty percent more than that in non-irradiated ones. With addition of 0.1% H 2 O 2 to the spirits be- fore irradiation, the electric potential changed even larger

Study of irradiation defects in GaAs

International Nuclear Information System (INIS)

Loualiche, S.

1982-11-01

Characterization techniques: C(V) differential capacity, DLTS deep level transient spectroscopy, DDLTS double deep level transient spectroscopy and DLOS deep level optical spectroscopy are studied and theoretical and experimental fundamentals are re-examined. In particular the centres created by ionic or electronic bombardment of p-type GaAs. New quantitative theoretical bases for the C(V) method are obtained. Study of the optical properties of traps due to irradiation using DLOS. The nature of irradiation defects are discussed [fr

Studies on preservation of agricultural products by irradiation

International Nuclear Information System (INIS)

Chung, K.H.; Kwon, S.H.; Lee, Y.I.; Chae, J.C.; Shin, I.C.

1981-01-01

This study was attempted to develop and establish the preservation techniques of agricultural products by irradiation through ascertainment of the optimum irradiation doses for sprout inhibition of white potato and chestnut, and for disinfestation of rice insects during storage

Specimen size effect considerations for irradiation studies of SiC/SiC

Energy Technology Data Exchange (ETDEWEB)

Youngblood, G.E.; Henager, C.H. Jr.; Jones, R.H. [Pacific Northwest National Lab., Richland, WA (United States)

1996-10-01

For characterization of the irradiation performance of SiC/SiC, limited available irradiation volume generally dictates that tests be conducted on a small number of relatively small specimens. Flexure testing of two groups of bars with different sizes cut from the same SiC/SiC plate suggested the following lower limits for flexure specimen number and size: Six samples at a minimum for each condition and a minimum bar size of 30 x 6.0 x 2.0 mm{sup 3}.

DC electrical conductivity of silicon carbide ceramics and composites for flow channel insert applications

International Nuclear Information System (INIS)

Katoh, Y.; Kondo, S.; Snead, L.L.

2009-01-01

High purity chemically vapor-deposited silicon carbide (SiC) and 2D continuous SiC fiber, chemically vapor-infiltrated SiC matrix composites with pyrocarbon interphases were examined. Specifically, temperature dependent (RT to 800 deg. C) electrical conductivity and the influence of neutron irradiation were measured. The influence of neutron irradiation on electrical properties appeared very strong for the SiC of this study, typically resulting in orders lower ambient conductivity and steeper temperature dependency of this conductivity. For the 2D composites, through-thickness (normal to the fiber axis') electrical conductivity was dominated by bypass conduction via interphase network at relatively low temperatures, whereas conduction through SiC constituents dominated at higher temperatures. Through-thickness electrical conductivity of neutron-irradiated 2D SiC composites with thin PyC interphase, currently envisioned for flow channel insert application, will likely in the order of 10 S/m at the appropriate operating temperature. Mechanisms of electrical conduction in the composites and irradiation-induced modification of electrical conductivity of the composites and their constituents are discussed.

Kr ion irradiation study of the depleted-uranium alloys

Science.gov (United States)

Gan, J.; Keiser, D. D.; Miller, B. D.; Kirk, M. A.; Rest, J.; Allen, T. R.; Wachs, D. M.

2010-12-01

Fuel development for the reduced enrichment research and test reactor (RERTR) program is tasked with the development of new low enrichment uranium nuclear fuels that can be employed to replace existing high enrichment uranium fuels currently used in some research reactors throughout the world. For dispersion type fuels, radiation stability of the fuel-cladding interaction product has a strong impact on fuel performance. Three depleted-uranium alloys are cast for the radiation stability studies of the fuel-cladding interaction product using Kr ion irradiation to investigate radiation damage from fission products. SEM analysis indicates the presence of the phases of interest: U(Al, Si) 3, (U, Mo)(Al, Si) 3, UMo 2Al 20, U 6Mo 4Al 43 and UAl 4. Irradiations of TEM disc samples were conducted with 500 keV Kr ions at 200 °C to ion doses up to 2.5 × 10 19 ions/m 2 (˜10 dpa) with an Kr ion flux of 10 16 ions/m 2/s (˜4.0 × 10 -3 dpa/s). Microstructural evolution of the phases relevant to fuel-cladding interaction products was investigated using transmission electron microscopy.

Progresses in studies on 2-alkylcyclobutanones in irradiated lipid-containing foods

International Nuclear Information System (INIS)

Zhang Haiwei; Ha Yiming; Wang Feng

2007-01-01

When foods are irradiated, the free fatty acids and triacylglycerides in the food are decomposed to 2-alkylcyclobutanones (2-ACBs), which have been one of the focuses in food irradiation studies since they were dis- covered in irradiated lipid-containing foods. As specific markers, 2-ACBs could be used to detect irradiated food. The production and stability of 2-ACBs are affected strongly by the irradiation does and temperature and preservation conditions, etc. On the other hand, potential health hazard assessments of 2-ACBs have been studied extensively. Re- cent progresses in 2-ACBs detecting methods from irradiated food, toxicological studies on 2-ACBs, and factors affecting production and stability of 2-ACBs are reviewed in this paper. (authors)

Irradiation creep and swelling of various austenitic alloys irradiated in PFR and FFTF

Energy Technology Data Exchange (ETDEWEB)

Garner, F.A.; Toloczko, M.B. [Pacific Northwest National Lab., Richland, WA (United States)] [and others

1996-10-01

In order to use data from surrogate neutron spectra for fusion applications, it is necessary to analyze the impact of environmental differences on property development. This is of particular importance in the study of irradiation creep and its interactions with void swelling, especially with respect to the difficulty of separation of creep strains from various non-creep strains. As part of an on-going creep data rescue and analysis effort, the current study focuses on comparative irradiations conducted on identical gas-pressurized tubes produced and constructed in the United States from austenitic steels (20% CW 316 and 20% CW D9), but irradiated in either the Prototype Fast Reactor (PFR) in the United Kingdom or the Fast Flux Test Facility in the United States. In PFR, Demountable Subassemblies (DMSA) serving as heat pipes were used without active temperature control. In FFTF the specimens were irradiated with active ({+-}{degrees}5C) temperature control. Whereas the FFTF irradiations involved a series of successive side-by-side irradiation, measurement and reinsertion of the same series of tubes, the PFR experiment utilized simultaneous irradiation at two axial positions in the heat pipe to achieve different fluences at different flux levels. The smaller size of the DMSA also necessitated a separation of the tubes at a given flux level into two groups (low-stress and high-stress) at slightly different axial positions, where the flux between the two groups varied {le}10%. Of particular interest in this study was the potential impact of the two types of separation on the derivation of creep coefficients.

Food irradiation development: Malaysian perspective

International Nuclear Information System (INIS)

Zainon Othman

1997-01-01

Malaysia recognised the potential of food irradiation as a technology that can contribute to solving some preservation problems associated with local agricultural produce. Research studies in this technology were initiated in late 1970s and since 1985, all activities pertaining to R and D applications, adoption and technology transfer of food irradiation were coordinated by The National Working Committee on Food Irradiation which comprises of members from research institutes, universities, regulatory agencies and consumer association. To date, technical feasibility studies conducted on 7 food items / agricultural commodities of economic importance demonstrated the efficacy of irradiation in extending shelf-life, improving hygienic quality and overcoming quarantine barriers in trade. Presently, 1 multipurpose Co-60 irradiator (I MCi), 2 gammacells and an electron beam machine (3 MeV) are available at MINT for research and commercial runs. The Malaysian Standards on Guidelines for Irradiation of Food was formulated in 1992 to facilitate application by local food industries. However, Malaysia has not yet commercially adopt the technology. Among many factors contributing to the situation is the apparent lack of interest by food industries and consumers. Consumer attitude study indicated majority of consumers are still unaware of the benefits of the technology and expressed concern for the safety of process and irradiated products due to limited knowledge and adverse publicity by established consumer groups. Although the food processors indicate positive attitude towards food irradiation, there remain many factors delaying its commercial application such as limited knowledge, cost-benefit, logistics and consumer acceptance. On the regulatory aspect, approval is required from the Director-General of Ministry of Health prior to application of irradiation on food and sale of irradiated food but efforts are being geared towards approving irradiation of certain food

Facts about food irradiation: Genetic studies

International Nuclear Information System (INIS)

1991-01-01

Results published in the mid-1970s from the National Institute of Nutrition (NIN) in India showed increased numbers of polyploid cells in rats, mice, monkeys and malnourished children fed irradiated wheat products. This fact sheet considers the validity of these results. A large number of independent studies have been subsequently performed, and in none of these have results been obtained that support the NIN findings. The conclusion is that there is no evidence to link the consumption of irradiated food with any mutagenic effect. 3 refs

Irradiation preservation of seafood: Literature review

International Nuclear Information System (INIS)

Molton, P.M.

1987-10-01

The application of gamma-irradiation for extending the shelf life of seafood has been of interest for many years. This report reviews a number of studies on seafood irradiation conducted over the past several years. Topics covered include seafood irradiation techniques and dosages, species applicability and differences, the effects of packaging on seafood preservation, and changes in organoleptic acceptability as a result of irradiation. Particular attention is given to radiation effects (likely and unlikely) of concern to the public. These include the potential for generation of toxic chemical products, botulinum toxin production, and other health concerns. No scientifically defensible evidence of any kind was found for any harmful effect of irradiation of seafoods at the doses being considered (less than 300 krad), and all indications are that irradiation is an acceptable and needed additional tool for seafood preservation. 49 refs., 14 figs., 14 tabs

Irradiation preservation of seafood: Literature review

Energy Technology Data Exchange (ETDEWEB)

Molton, P.M.

1987-10-01

The application of gamma-irradiation for extending the shelf life of seafood has been of interest for many years. This report reviews a number of studies on seafood irradiation conducted over the past several years. Topics covered include seafood irradiation techniques and dosages, species applicability and differences, the effects of packaging on seafood preservation, and changes in organoleptic acceptability as a result of irradiation. Particular attention is given to radiation effects (likely and unlikely) of concern to the public. These include the potential for generation of toxic chemical products, botulinum toxin production, and other health concerns. No scientifically defensible evidence of any kind was found for any harmful effect of irradiation of seafoods at the doses being considered (less than 300 krad), and all indications are that irradiation is an acceptable and needed additional tool for seafood preservation. 49 refs., 14 figs., 14 tabs.

UKAEA code of practice for tracer and irradiation studies involving the use of volunteers

International Nuclear Information System (INIS)

Pritchard, J.N.; Morgan, A.

1987-06-01

The subject is discussed under the following headings: 1) General considerations in volunteer studies (informed consent, beneficial objectives, recruitment from within or without the workforce, records, compensation, codes of practice, confidentiality etc.) 2) Tracer and irradiation studies approval committee, (terms of reference, membership, dose limitations, assessment of chemical toxicity, procedure for submitting proposals) 3) Obtaining a project licence 4) Conduct of volunteer experiments 5) The use of non-authority volunteers. (U.K.)

Techno-economic studies on transportable moving-bed onion irradiator

International Nuclear Information System (INIS)

Krishnamurthy, K.; Sharma, K.S.S.; Deshmukh, V.P.; Bongirwar, D.R.; Nair, K.V.V.; Patil, K.B.

1984-01-01

The paper presents the optimisation studies and the design features of a transportable irradiator evolved to demonstrate the techno-economic advantage of the irradiation process at village level. A brief outline is also given of the computer programme generated and employed to optimise the source-target configuration based on a narrow plane source moving-bed irradiation concept that aimed at achieving a simplified product handling system and cost effective design of the biological shield and controls for the irradiator. The engineering features of the irradiator along with a summary of the analysis of the economics of the application of the process are also given. (author)

Electrical in situ and post-irradiation properties of ceramics relevant to fusion irradiation conditions

International Nuclear Information System (INIS)

Shikama, Tatsuo; Zinkle, S.J.

2002-01-01

Electrical properties of ceramic candidate materials for the next-generation nuclear fusion devices under relevant irradiation conditions are reviewed. A main focal point is placed on the degradation behavior of the electrical insulating ability during and after irradiation. Several important radiation induced effects play important roles: radiation induced conductivity, thermally stimulated electrical conductivity, radiation induced electrical charge separation, and radiation induced electromotive force. These phenomena will interact with each other under fusion relevant irradiation conditions. The design of electrical components for the next-generation fusion devices should take into account these complicated interactions among the radiation induced phenomena

Irradiation processing of potatoes, onions and garlic

International Nuclear Information System (INIS)

Jan, M.; Starr, A.; Wahid, M.; Ahmad, A.; Khan, I.

1992-07-01

In this report, studies have been conducted on irradiation preservation of potatoes, onions and garlic involving different varieties, harvesting season and storage life. As a result of these investigations, optimum conditions were established for each crop. The effect of irradiation and storage on sprouting, rottage and weight loss of potatoes is presented. The sprouting initiated in the unirradiated samples after 2 months reaching 51, 80 and 100% on 4, 5 and 6 months storage respectively. Weight losses were observed in the irradiated and unirradiated samples. (A.B.)

One-step synthesis of high conductivity silver nanoparticle-reduced graphene oxide composite films by electron beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Liu, Gang; Wang, Yujia; Pu, Xianjuan; Jiang, Yong; Cheng, Lingli, E-mail: chenglingli@shu.edu.cn; Jiao, Zheng, E-mail: zjiao@shu.edu.cn

2015-09-15

Graphical abstract: - Highlights: • Both graphene oxide and silver ion were reduced simultaneously by electron beam-based method. • The size of AgNPs can be controlled by changing the irradiation dose of electron beam. • The AgNPs/rGO nanocomposite exhibits much lower sheet resistivity (0.06 Ω m). - Abstract: A rapid, eco-friendly, one-step electron beam (EB)-based method for both the reduction of graphene oxide and loading of Ag nanoparticles (AgNPs) were achieved. Further, the effects of irradiation dose on the morphology of AgNPs and the sheet resistance of Ag nanoparticles/reduced graphene oxide (AgNPs/rGO) were studied. The results reveal that when the irradiation dose increased from 70 kGy to 350 kGy, the size of the AgNPs decreased and became uniformly distributed over the surface of the rGO nanosheets. However the size of the AgNPs increased when the irradiation dose reached 500 kGy. Four-point probe measurement showed that the sheet resistance of the AgNPs/rGO films decreased with decreasing AgNPs size. The lowest sheet resistivity of 0.06 Ω m was obtained in the film corresponding to 350 kGy irradiation dose, which showed a much lower resistivity than the GO film (5.04 × 10{sup 5} Ω m). The formation mechanisms of the as-prepared AgNPs/rGO nanocomposites were proposed. This study provides a fast and eco-friendly EB irradiation induced method to controlling the dimensions of AgNPs/rGO nanocomposites, which can strongly support the mass production of AgNPs/rGO nanocomposites for practical applications.

One-step synthesis of high conductivity silver nanoparticle-reduced graphene oxide composite films by electron beam irradiation

International Nuclear Information System (INIS)

Liu, Gang; Wang, Yujia; Pu, Xianjuan; Jiang, Yong; Cheng, Lingli; Jiao, Zheng

2015-01-01

Graphical abstract: - Highlights: • Both graphene oxide and silver ion were reduced simultaneously by electron beam-based method. • The size of AgNPs can be controlled by changing the irradiation dose of electron beam. • The AgNPs/rGO nanocomposite exhibits much lower sheet resistivity (0.06 Ω m). - Abstract: A rapid, eco-friendly, one-step electron beam (EB)-based method for both the reduction of graphene oxide and loading of Ag nanoparticles (AgNPs) were achieved. Further, the effects of irradiation dose on the morphology of AgNPs and the sheet resistance of Ag nanoparticles/reduced graphene oxide (AgNPs/rGO) were studied. The results reveal that when the irradiation dose increased from 70 kGy to 350 kGy, the size of the AgNPs decreased and became uniformly distributed over the surface of the rGO nanosheets. However the size of the AgNPs increased when the irradiation dose reached 500 kGy. Four-point probe measurement showed that the sheet resistance of the AgNPs/rGO films decreased with decreasing AgNPs size. The lowest sheet resistivity of 0.06 Ω m was obtained in the film corresponding to 350 kGy irradiation dose, which showed a much lower resistivity than the GO film (5.04 × 10 5 Ω m). The formation mechanisms of the as-prepared AgNPs/rGO nanocomposites were proposed. This study provides a fast and eco-friendly EB irradiation induced method to controlling the dimensions of AgNPs/rGO nanocomposites, which can strongly support the mass production of AgNPs/rGO nanocomposites for practical applications

Study on the sterilization of egg white powder by irradiation

International Nuclear Information System (INIS)

Fu Lixin; Meng Lifen; Zhao Xiaonan; Xu Dechun; Hu Shaoxin; Chen Changdong; Wang Zhidong

2013-01-01

The sterilizing effect, influence on main essential nutrient and sensory qualities of egg white powder treated with 60 Co γ-ray irradiation were studied. The microorganism index of egg white powder samples treated with 4 kGy irradiation could meet the government food sanitation standard, and the sterilization rate could reach 100%. The irradiation doses from 4 to 10 kGy had little influence on egg white powder protein, crude fiber and amino acidscontent, and the sensory quality such as color, luster, and scent changed little below 6 kGy irradiation. Considering the result of this study, the optimal irradiation dose for egg white powder sterilization was 4 to 6 kGy. (authors)

Pathological study about two autopsy cases of bilateral irradiation pneumonitis induced by unilateral irradiation

International Nuclear Information System (INIS)

Yamauchi, Noriko; Tajima, Yo; Iio, Masaaki; Oshima, Takeo; Iino, Koichi.

1978-01-01

The first case is a 73-year-old man with left lung cancer. Seven days after completion of radiotherapy 7,000 rad, a chest roentgenogram showed diffuse bilateral pneumonia. The second case is a 61-year-old woman with right lung cancer and about one month after completion of radiotherapy 2,600 rad, a chest roentgenogram showed bilateral pneumonia. Pathological findings, all lobes of both lungs of these cases showed acute interstitial pneumonitis. The pathogenesis of irradiation pneumonitis is poorly understood. Several investigators thought that the pathogenesis of irradiation pneumonitis was caused by autoimmune mechanism, they carried out sero-pathological studies and demonstrated the bilateral pneumonia caused by unilateral irradiation. (author)

Cytologic studies on irradiated gestric cancer cells

Energy Technology Data Exchange (ETDEWEB)

Isono, S; Takeda, T; Amakasu, H; Asakawa, H; Yamada, S [Miyagi Prefectural Adult Disease Center, Natori (Japan)

1981-06-01

The smears of the biopsy and resected specimens obtained from 74 cases of irradiated gastric cancer were cytologically analyzed for effects of irradiation. Irradiation increased the amount of both necrotic materials and neutrophils in the smears. Cancer cells were decreased in number almost in inverse proportion to irradiation dose. Clusters of cancer cells shrank in size and cells were less stratified after irradiation. Irradiated cytoplasms were swollen, vacuolated and stained abnormally. Irradiation with less than 3,000 rads gave rise to swelling of cytoplasms in almost all cases. Nuclei became enlarged, multiple, pyknotic and/or stained pale after irradiation. Nuclear swelling was more remarkable in cancer cells of differentiated adenocarcinomas.

NMR studies of defects created by irradiation in metals

International Nuclear Information System (INIS)

Minier, M.; Minier, C.

1983-06-01

Nuclear Magnetic Resonance has been rarely used to study point defects created by irradiation in metals. Information obtained in this field using N.M.R. are shown. Some results are also described: characterization of migrating defects in electron irradiated copper; mobility of the complex interstitial-impurity in Al with 150 ppm of chromium; interstitial structure in irradiated aluminum and autodiffusion in metals [fr

Surface study of irradiated sapphires from Phrae Province, Thailand using AFM

Science.gov (United States)

Monarumit, N.; Jivanantaka, P.; Mogmued, J.; Lhuaamporn, T.; Satitkune, S.

2017-09-01

The irradiation is one of the gemstone enhancements for improving the gem quality. Typically, there are many varieties of irradiated gemstones in the gem market such as diamond, topaz, and sapphire. However, it is hard to identify the gemstones before and after irradiation. The aim of this study is to analyze the surface morphology for classifying the pristine and irradiated sapphires using atomic force microscope (AFM). In this study, the sapphire samples were collected from Phrae Province, Thailand. The samples were irradiated by high energy electron beam for a dose of ionizing radiation at 40,000 kGy. As the results, the surface morphology of pristine sapphires shows regular atomic arrangement, whereas, the surface morphology of irradiated sapphires shows the nano-channel observed by the 2D and 3D AFM images. The atomic step height and root mean square roughness have changed after irradiation due to the micro-structural defect on the sapphire surface. Therefore, this study is a frontier application for sapphire identification before and after irradiation.

Scanning ion irradiation of polyimide films

Energy Technology Data Exchange (ETDEWEB)

Luecken, Stefan; Koval, Yuri; Mueller, Paul [Department of Physics and Interdisciplinary Center for Molecular Materials (ICMM), Universitaet Erlangen-Nuernberg (Germany)

2012-07-01

Recently we found, that the surface of nearly any polymer can be converted into conductive material by low energy ion irradiation. The graphitized layer consists of nanometer sized graphene and graphite flakes. In order to enhance the conductivity and to increase the size of the flakes we applied a novel method of scanning irradiation. We investigated the influence of various irradiation parameters on the conductivity of the graphitized layer. We show, that the conductance vs. temperature can be described in terms of weak Anderson localization. At approximately 70 K, a crossover occurs from 2-dimensional to 3-dimensional behavior. This can be explained by a decrease of the Thouless length with increasing temperature. The crossover temperature can be used to estimate the thickness of the graphitized layer.

All-photonic drying and sintering process via flash white light combined with deep-UV and near-infrared irradiation for highly conductive copper nano-ink

Science.gov (United States)

Hwang, Hyun-Jun; Oh, Kyung-Hwan; Kim, Hak-Sung

2016-01-01

We developed an ultra-high speed photonic sintering method involving flash white light (FWL) combined with near infrared (NIR) and deep UV light irradiation to produce highly conductive copper nano-ink film. Flash white light irradiation energy and the power of NIR/deep UV were optimized to obtain high conductivity Cu films. Several microscopic and spectroscopic characterization techniques such as scanning electron microscopy (SEM), a x-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy were employed to characterize the Cu nano-films. Optimally sintered Cu nano-ink films produced using a deep UV-assisted flash white light sintering technique had the lowest resistivity (7.62 μΩ·cm), which was only 4.5-fold higher than that of bulk Cu film (1.68 μΩ•cm). PMID:26806215

Xenon migration in UO{sub 2} under irradiation studied by SIMS profilometry

Energy Technology Data Exchange (ETDEWEB)

Marchand, B. [Université de Lyon, CNRS/IN2P3, Université Lyon 1, Institut de Physique Nucléaire de Lyon, 4 rue Enrico Fermi, F-69622 Villeurbanne cedex (France); AREVA, AREVA NP, 10 rue Juliette Récamier, F-69456 Lyon (France); Moncoffre, N. [Université de Lyon, CNRS/IN2P3, Université Lyon 1, Institut de Physique Nucléaire de Lyon, 4 rue Enrico Fermi, F-69622 Villeurbanne cedex (France); Pipon, Y., E-mail: pipon@ipnl.in2p3.fr [Université de Lyon, CNRS/IN2P3, Université Lyon 1, Institut de Physique Nucléaire de Lyon, 4 rue Enrico Fermi, F-69622 Villeurbanne cedex (France); Université de Lyon, Université Lyon 1, IUT Lyon 1, 43 bd du 11 novembre 1918, 69 622 Villeurbanne cedex (France); Bérerd, N. [Université de Lyon, CNRS/IN2P3, Université Lyon 1, Institut de Physique Nucléaire de Lyon, 4 rue Enrico Fermi, F-69622 Villeurbanne cedex (France); Université de Lyon, Université Lyon 1, IUT Lyon 1, 43 bd du 11 novembre 1918, 69 622 Villeurbanne cedex (France); Garnier, C. [AREVA, AREVA NP, 10 rue Juliette Récamier, F-69456 Lyon (France); Raimbault, L. [Ecole des Mines de Paris, Centre de Géosciences, 35 rue Saint Honoré, F-77305 Fontainebleau cedex (France); Sainsot, P. [Université de Lyon, Université Lyon 1, LaMCoS, INSA-Lyon, CNRS UMR5259, F-69621 Villeurbanne cedex (France); and others

2013-09-15

During Pressurized Water Reactor operation, around 25% of the created Fission Products (FP) are Xenon and Krypton. They have a low solubility in the nuclear fuel and can either (i) agglomerate into bubbles which induce mechanical stress in the fuel pellets or (ii) be released from the pellets, increasing the pressure within the cladding and decreasing the thermal conductivity of the gap between pellets and cladding. After fifty years of studies on the nuclear fuel, all mechanisms of Fission Gas Release (FGR) are still not fully understood. This paper aims at studying the FGR mechanisms by decoupling thermal and irradiation effects and by assessing the Xenon behavior for the first time by profilometry. Samples are first implanted with {sup 136}Xe at 800 keV corresponding to a projected range of 140 nm. They are then either annealed in the temperature range 1400–1600 °C, or irradiated with heavy energy ions (182 MeV Iodine) at Room Temperature (RT), 600 °C or 1000 °C. Depth profiles of implanted Xenon in UO{sub 2} are determined by Secondary Ion Mass Spectrometry (SIMS). It is shown that Xenon is mobile during irradiation at 1000 °C. In contrast, thermal treatments do not induce any Xenon migration process: these results are correlated to the formation of Xenon bubbles observed by Transmission Electron Microscopy.

Effect of irradiation on biochemistry properties of shrimp allergen

International Nuclear Information System (INIS)

Gu Kefei; Gao Meixu; Li Chunhong; Li Shurong; Pan Jiarong

2007-01-01

Study on the effects of 60 Co γ-rays irradiation at the dose of 0,3,5,7,10 kGy on shrimp allergen biochemistry properties was conducted. The results indicated that the allergen protein molecule can be broken down to smaller molecules or coagulated to larger molecules by irradiation. The hydrophobicity and turbidity of irradiated allergen increased with the increase of absorbed dose. The results also show that allergen solution is more sensitive to irradiation than allergen in solid state or in the whole shrimp. (authors)

Spectroscopic study of gamma irradiated bovine hemoglobin

International Nuclear Information System (INIS)

Maghraby, Ahmed Mohamed; Ali, Maha Anwar

2007-01-01

In the present study, the effects of ionizing radiation of Cs-137 and Co-60 from 4.95 to 743.14 Gy and from 40 Gy to 300 kGy, respectively, on some bovine hemoglobin characteristics were studied. Such an effect was evaluated using electron paramagnetic resonance (EPR) spectroscopy, and infra-red (IR) spectroscopy. Bovine hemoglobin EPR spectra were recorded and analyzed before and after irradiation and changes were explained in detail. IR spectra of unirradiated and irradiated Bovine hemoglobin were recorded and analyzed also. It was found that ionizing radiation may lead to the increase of free radicals production, the decrease in α-helices contents, which reflects the degradation of hemoglobin molecular structure, or at least its incomplete performance. Results also show that the combined application of EPR and FTIR spectroscopy is a powerful tool for determining structural modification of bovine hemoglobin samples exposed to gamma irradiation

Heavy-Section Steel Irradiation Program

International Nuclear Information System (INIS)

Corwin, W.R.

1990-08-01

The primary goal of the Heavy-Section Steel Irradiation Program is to provide a thorough, quantitative assessment of the effects of neutron irradiation on the material behavior (particularly the fracture toughness properties) of typical pressure-vessel steels as they relate to light-water-reactor pressure-vessel integrity. The program includes direct continuation of irradiation studies previously conducted by the Heavy-Section Steel Technology Program augmented by enhanced examinations of the accompanying microstructural changes. Effects of specimen size; material chemistry; product form and microstructure; irradiation fluence, flux, temperature, and spectrum; and postirradiation annealing are examined on a wide range of fracture properties. Detailed statistical analyses of the fracture data on K Ic shift of high-copper welds were performed. Analysis of the first phase of irradiated crack-arrest testing on high-copper welds was completed. Final analysis and publication of the results of the second phase of the irradiation studies on stainless steel weld-overlay cladding were completed. Determinations were made of the variations in chemistry and unirradiated RT NDT of low upper-shelf weld metal from the Midland reactor. Final analyses were performed on the Charpy impact and tensile data from the Second and Third Irradiation series on low upper-shelf welds, and the report on the series was drafted. A detailed survey of existing data on microstructural models and data bases of irradiation damage was performed, and initial development of a reaction-rate-based model was completed. 40 refs., 7 figs., 4 tabs

Study on irradiation preservation of frozen shelled shrimps

International Nuclear Information System (INIS)

Liu Chunquan; Zhu Jiating; Zhao Yongfu; Yu Gang; Zhang Weidong; Jin Yudong; Ji Ping

2004-01-01

The effect of irradiaiton preservation of frozen shelled shrimps for export was studied. The microbial indexd, nutritional ingredient, physico-chemical index for irradiation frozen shelled shrimps were detected. The results showed that 3-5 kGy irradiation dose could kill more than 99% of all kinds of microorganisms in frozen shelled shrimps, the content of most amino acids in shelled shrimps increased, after being irradiated by 1-9 kGy dose, the total amino acids had been obvisouly higher than CK, the increased range was 0.33%-24.6%, the content of the total volatile basic nitrogen (TVBN) decreased. Compared with the CK, the content of the heavy metal elements etc had no obvious change, the presrvation duration of irradiated shelled shrimp was twelve months longer than that of CK when storage temperature was under -7 degree C soft frozen, Compared with -18 degree C the effect of irradiation preservation had no obvious change. (authors)

Special irradiation techniques

International Nuclear Information System (INIS)

Colomez, Gerard; Veyrat, J.F.

1981-01-01

Irradiation trials conducted on materials-testing reactors should provide a better understanding of the phenomena which characterize the working and evolution in time of electricity-generating nuclear reactors. The authors begin by outlining the objectives behind experimental irradiation (applied to the various nuclear chains) and then describe the special techniques deployed to achieve these objectives [fr

Studies on apple preservation by 60 -gamma irradiation

International Nuclear Information System (INIS)

Wang Chuanyao; Jiang Mengyue; Gao Meixu

1992-01-01

Studies on '60'Co-gamma irradiation of Golden Delicious apple have been carried out. The results showed that the optimum irradiation dosage for stored apple was ranged from 0.3-0.5 k Gy, with this dosage, the contents of vitamin c and titratalbe acidity in these apples had no significant change compared with unirradiated apples. The respiratory rate and the amount of ethylene release were decreased after irradiation. The mortality of the verticillate pathogenic fungi was 97% at the dose of 0.5 k Gy

Gamma- and electron dose response of the electrical conductivity of polyaniline based polymer blends

International Nuclear Information System (INIS)

Sevil, U.A.; Gueven, O.; Slezsak, I.

2002-01-01

Complete text of publication follows. Conducting polymers, also known as 'synthetic metals' have been the subject of widespread investigations over the past decade due to their very promising characteristics. Polyaniline (PANI) holds a special position among conducting polymers in that its most highly conducting doped form can be reached by protonic acid doping or oxidative doping. It was published earlier, that the electrical conductivity of some polyaniline based polymer composites increases to a significant extent when irradiated to gamma, electron or UV radiation. The aim of the present study was to measure the high frequency conductivity of blended films of PANI with poly(vinylchloride), PVC, and chlorinated poly(propylene) irradiated in air to different doses. In order to find the most suitable composition od these composites the mass percentage of PANI within the PPCl and PVC matrix was changed between 5 - 30%. These samples were then gamma irradiated and the induced electrical conductivity was measured in the 1 kHz - 1 MHz frequency range to determine the most sensitive evaluation conditions. After selecting both the most suitable measuring conditions as well as the blend compositions the dose response of the chosen samples was determined in the dose range of 10 - 250 kGy. With respect to potential dosimetry application the effect of electron irradiation, the effect of irradiation temperature and the stability of the irradiated samples have also been investigated

A low-energy x-ray irradiator for electrophysiological studies

International Nuclear Information System (INIS)

Schauer, D.A.; Zeman, G.H.; Pellmar, T.C.

1989-01-01

A 50 kVp molybdenum target/filter x-ray tube has been installed inside a lead-shielded Faraday cage. High-dose rates of up to 1.54 Gy min -1 (17.4 keV weighted average photons) have been used to conduct local in vitro irradiations of the hippocampal region of guinea pig brains. Electrophysiological recordings of subtle changes in neuronal activity indicate this system is suitable for this application. (author)

Studies on the safety and consumer acceptance of gamma irradiated meats

Energy Technology Data Exchange (ETDEWEB)

Kang, Il Jun [Hallym University, Kangwon (Korea); Lee, Cherl Ho [Korea University, Seoul (Korea); Kim, Jung Hee [Seoul Women' s University, Seoul (Korea)

1999-04-01

Gamma irradiation was applied to beefs (0-5 kGy) and porks (0-30 kGy) for evaluation of their possible genotoxicity, acute toxicity and four-week oral toxicity. The results were negative in the bacterial reversion assay with S. typhimurium TA98, TA100, TA1535, TA1537. Clastogenic effects of the irradiated samples tested were not shown in vivo mouse micronucleus assay. In an acute toxicity test, the maximal dose of 5,000 mg/kg did not change any toxic parameter examined in this study. In four-week oral toxicity study, no significant differences were found between the control and treatment groups. In the study of rat hepatocarcinogenesis, the consumption of gamma irradiated beef and pork not only does not affect the formation of lipid peroxide and membrane stability but also has a possibility to inhibit hepatocarcinogenesis. Also, the consumption of {gamma} - irradiated beef and pork does not affect antioxidative defense system. In the study of the biological safety of korean red pepper, no difference was found on microbial growth between pepper extract alone or irradiated pepper extract. In the preservation study of korean traditional rice-cake(garedok), irradiation dose below 10kGy had no influence on typical sensory characteristics. The shelf-life in rice-cakes with different conditions was the longest on 10kGy treatment than 5kGy. In investigation of the consumer attitude toward irradiated foods, the main reason for the concern about irradiated foods is that compounds in the products formed by irradiation. Therefore, regulatory authorities must be encouraged to permit the sale of irradiated items when wholesomeness is established. (author). 94 refs.,31 figs., 62 tabs.

U-target irradiation at FRM II aiming the production of Mo-99 - A feasibility study

International Nuclear Information System (INIS)

Gerstenberg, H.; Mueller, C.; Neuhaus, I.; Roehrmoser, A.

2010-01-01

Following the shortage in radioisotope availability the Technische Unversitaet Muenchen and the Belgian Institut National des Radioelements conducted a common study on the suitability of the FRM II reactor for the generation of Mo-99 as a fission product. A suitable irradiation channel was determined and neutronic calculations resulted in sufficiently high neutron flux densities to make FRM II a promising candidate for Mo-99 production. In addition the feasibility study provides thermohydraulic calculations as input for the design and integration of the additional cooling circuit into the existing heat removal systems of FRM II. The required in-house processes for a regular uranium target irradiation programme have been defined and necessary upgrades identified. Finally the required investment cost was estimated and a possible time schedule was given. (author)

Characterization of un-irradiated and irradiated reactor graphite; Karakterizacija neozracenog i ozracenog reaktorskog grafita

Energy Technology Data Exchange (ETDEWEB)

Marinkovic, S [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

1965-11-15

This report contains three parts: characterization of Yugoslav nuclear graphite development of methods and obtained results, characterization of un-irradiated and irradiated domestic nuclear graphite; calculation of electrical conductivity changes due to vacancies in the graphite crystal lattice.

Performance studies under high irradiation of resistive bulk-micromegas chambers at the CERN Gamma Irradiation Facility

CERN Document Server

Sidiropoulou, Ourania; Bortfeldt, J; Farina, E; Iengo, P; Longo, L; Sidiropoulou, O; Wotschack, J

2017-01-01

Radiation studies on several resistive bulk-Micromegas chambers produced at CERN will be viewed in this document. Two resistive bulk-Micromegas chambers have been installed at the CERN Gamma Irradiation Facility (GIF++) exposed to an intense gamma irradiation with the aim of evaluating the detector behaviour under high irradiation and carrying out a long-term age- ing study. The chambers under study have an active area of 10 x 10 cm 2 , a strip pitch of 400 m m , an ampli- fication gap of 128 m m , and a drift gap of 5 mm. The results on the detector performance as a function of the photon flux up to 44 MHz/cm 2 will be shown as well as the ageing properties as function of the integrated charge and the current intensity and its stability with time. In addition, the results of the efficiency measurements before, during, and after the irradiation will also be presented as a function of the amplification voltage at which the chambers are operated.

EPR study on gamma-irradiated fruits dehydrated via osmosis

International Nuclear Information System (INIS)

Yordanov, N.D.; Aleksieva, K.

2007-01-01

The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and γ-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas γ-irradiated exhibit 'sugar-like' EPR spectra. The recorded EPR spectra are monitored for a period of 7 months after irradiation (stored at low humidity and in the dark). The results suggest longer period of unambiguous identification of the radiation processing of osmose dehydrated fruits. Therefore, the Protocol EN 13708,2001 issued by CEN is fully applicable for the studied fruit samples

Stereophotogrammetric study of surface topography in ion irradiated silver

International Nuclear Information System (INIS)

Sokolov, V.N.; Fayazov, I.M.

1993-01-01

The irradiated surface topography of polycrystalline silver was studied using the stereophotogrammetric method. The surface of silver was irradiated with 30 keV argon ions at variation for the ion incidence angle in interval of 0-80 deg relative to a surface normal. The influence of the inclination angle of the sample in the SEM on the cone shape of a SEM-picture of the irradiated surface is discussed. The parameters of cones on the irradiated surface of silver were measured by the SEM-stereomethod. The measurements of the sample section perpendicular to the incidence plane are also carried out

EPR study on gamma-irradiated fruits dehydrated via osmosis

Science.gov (United States)

Yordanov, N. D.; Aleksieva, K.

2007-06-01

The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and γ-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas γ-irradiated exhibit "sugar-like" EPR spectra. The recorded EPR spectra are monitored for a period of 7 months after irradiation (stored at low humidity and in the dark). The results suggest longer period of unambiguous identification of the radiation processing of osmose dehydrated fruits. Therefore, the Protocol EN 13708,2001 issued by CEN is fully applicable for the studied fruit samples.

A study on mice exposure dose for low-dose gamma-irradiation using glass dosimeter

Energy Technology Data Exchange (ETDEWEB)

Noh, Sung Jin; Kim, Hyo Jin; Kim, Hyun; Jeong, Dong Hyeok; Son, Tae Gen; Kim, Jung Ki; Yang, Kwang Mo; Kang, Yeong Rok [Research Center, Dongnam Institute of Radiological and Medical Sciences, Busan (Korea, Republic of); Nam, Sang Hee [Dept. of Biomedical Engineering, Inje University, Gimhae (Korea, Republic of)

2015-12-15

The low dose radiation is done for a long period, thus researchers have to know the exact dose distribution for the irradiated mouse. This research has been conducted in order to find out methods in transmitting an exact dose to mouse in a mouse irradiation experiment carried out using {sup 137}C{sub s} irradiation equipment installed in the DIRAMS (Dongnam Institution of Radiological and Medical Sciences) research center. We developed a single mouse housing cage and shelf with adjustable geometric factors such as distance and angle from collimator. The measurement of irradiated dose showed a maximal 42% difference of absorbed dose from the desired dose in the conventional irradiation system, whereas only 6% difference of the absorbed dose was measured in the self-developed mouse apartment system. In addition, multi mice housing showed much difference of the absorbed dose in between head and body, compared to single mouse housing in the conventional irradiation system. This research may allow further research about biological effect assessment for the low dose irradiation using the self-developed mouse apartment to provide more exact doses which it tries to transmit, and to have more reliability for the biological analysis results.

Preliminary study on sterilization effect of irradiation on dry vegetable

International Nuclear Information System (INIS)

Zhai Jianqing; Bao Jianzhong; Cao Hong; Wang Jinrong; Chen Xiulan

2004-01-01

The number of surviving germs relationship to irradiation dose for several species dry vegetable was studied, and the original value D 10 of the dry vegetable was given. The value will provide a theoretical reference to ascertain the appropriate irradiation dose in the irradiation process of the dry vegetable

Construction of an apparatus for measuring the low-temperature thermal conductivity before and after neutron irradiation. Application to uranium dioxide (1963); Realisation d'un appareil pour la mesure de la conductibilite thermique a basse temperature avant et apres irradiation neutronique. Application au dioxyde d'uranium (1963)

Energy Technology Data Exchange (ETDEWEB)

Bethoux, O [Commisariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1963-09-15

An apparatus has been studied and built which makes it possible to alternatively irradiate a sample at room temperature in the reactor 'Melusine' at the Grenoble Nuclear Research Centre, and to measure its thermal conductivity between 20 and 100 deg. K in perfect safety. The results obtained on UO{sub 2} have made it possible on the one hand to check experimentally that the spin-phonon diffusion leads to a thermal resistance independent of temperature above 30 deg. K, and on the other hand to propose a simple theory which takes into count the role played by the damage due to U-235 fission products in the decrease of thermal conductivity after irradiation. (author) [French] Un appareil permettant alternativement d'irradier un echantillon a temperature ambiante dans le reacteur ''Melusine'' du C.E.N.G., et de mesurer sa conductibilite thermique entre 20 et 100 deg. K en toute securite, a ete etudie et construit Les resultats obtenus sur UO{sub 2} ont permis, d'une part, de verifier experimentalement que la diffusion spin-phonon conduit a une resistance thermique independante de la temperature au-dessus de 30 deg. K, et, d'autre part, de proposer une theorie simple tenant compte du role joue par les degats dus aux produits de fission de l'uranium 235, dans la deterioration de la conductibilite thermique apres irradiation. (auteur)

Kr ion irradiation study of the depleted-uranium alloys

Energy Technology Data Exchange (ETDEWEB)

Gan, J., E-mail: Jian.Gan@inl.go [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States); Keiser, D.D. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States); Miller, B.D. [University of Wisconsin, 1500 Engineering Drive, Madison, WI 53706 (United States); Kirk, M.A.; Rest, J. [Argonne National Laboratory, 9700 South Cass Ave., Argonne, IL 60439 (United States); Allen, T.R. [University of Wisconsin, 1500 Engineering Drive, Madison, WI 53706 (United States); Wachs, D.M. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-6188 (United States)

2010-12-01

Fuel development for the reduced enrichment research and test reactor (RERTR) program is tasked with the development of new low enrichment uranium nuclear fuels that can be employed to replace existing high enrichment uranium fuels currently used in some research reactors throughout the world. For dispersion type fuels, radiation stability of the fuel-cladding interaction product has a strong impact on fuel performance. Three depleted-uranium alloys are cast for the radiation stability studies of the fuel-cladding interaction product using Kr ion irradiation to investigate radiation damage from fission products. SEM analysis indicates the presence of the phases of interest: U(Al, Si){sub 3}, (U, Mo)(Al, Si){sub 3}, UMo{sub 2}Al{sub 20}, U{sub 6}Mo{sub 4}Al{sub 43} and UAl{sub 4}. Irradiations of TEM disc samples were conducted with 500 keV Kr ions at 200 {sup o}C to ion doses up to 2.5 x 10{sup 19} ions/m{sup 2} ({approx}10 dpa) with an Kr ion flux of 10{sup 16} ions/m{sup 2}/s ({approx}4.0 x 10{sup -3} dpa/s). Microstructural evolution of the phases relevant to fuel-cladding interaction products was investigated using transmission electron microscopy.

Enhancement of conductance of GaAs sub-microwires under external stimuli

Science.gov (United States)

Qu, Xianlin; Deng, Qingsong; Zheng, Kun

2018-03-01

Semiconductors with one dimension on the micro-nanometer scale have many unique physical properties that are remarkably different from those of their bulk counterparts. Moreover, changes in the external field will further modulate the properties of the semiconductor micro-nanomaterials. In this study, we used focused ion beam technology to prepare freestanding ⟨111⟩-oriented GaAs sub-microwires from a GaAs substrate. The effects of laser irradiation and bending or buckling deformation induced by compression on the electrical transport properties of an individual GaAs sub-microwire were studied. The experimental results indicate that both laser irradiation and bending deformation can enhance their electrical transport properties, the laser irradiation resulted in a conductance enhancement of ˜30% compared to the result with no irradiation, and in addition, bending deformation changed the conductance by as much as ˜180% when the average strain was approximately 1%. The corresponding mechanisms are also discussed. This study provides beneficial insight into the fabrication of electronic and optoelectronic devices based on GaAs micro/nano-wires.

Detection of irradiated potatoes by impedance measurement

International Nuclear Information System (INIS)

Hayashi, T.; Todoriki, S.; Otobe, K.; Sugiyama, J.

1996-01-01

Potato is one of the major food items to be treated with ionising radiation and potatoes are irradiated on a large scale in several countries. Every year around 15,000 t of potatoes are irradiated at doses of 60 to 150 Gy (average dose is about 100 Gy) in Japan. Although various methods to detect irradiated potatoes have been investigated, no established method has been reported. Measuring electrical conductivity or impedance of potatoes has been reported as a promising method for the detection of irradiated potatoes. In previous studies it has been found that the ratio of impedance magnitude at 50 kHz to that at 5 kHz, measured immediately after puncturing a potato tuber, is dependent upon the dose applied to the tuber, independent of storage temperature and stable during storage after irradiation. The aim of this study was to establish the optimum conditions for impedance measurement and to examine the applicability of the impedance measuring method to various cultivars (cv.) of potatoes. (author)

Biophysical study of mice blood after whole body irradiation

Science.gov (United States)

Saad El Din, Alsha A.; Desouky, Omar S.; El Behay, Amin Z.; El Sayed, Anwar A.

1996-05-01

The immediate of whole body fractionated doses of 137Cs gamma rays totalling 13 Gy on mice as well as the late effects of accumulative dose of 10 Gy (8 days after exposure) were studied. Changes due to gamma irradiation in hemoglobin conductivity and buffer capacity indicate the appearance of hydrophobic groups and changes in hydrophilic/hydrophobic ratio. These changes demonstrate different degrees of unfolding and refolding of the hemoglobin molecule. The viscosity coefficient of hemoglobin is found to increase at fractionated doses of 7 and 13 Gy. Such effect seems to be due to aggregation of the protein part of hemoglobin. The fractionated dose of 13 Gy causes changes in the electronic state of oxyhemoglobin indicated by an increase in methemoglobin which reduces biological activity.

Space charge dynamic of irradiated cyanate ester/epoxy at cryogenic temperatures

Science.gov (United States)

Wang, Shaohe; Tu, Youping; Fan, Linzhen; Yi, Chengqian; Wu, Zhixiong; Li, Laifeng

2018-03-01

Glass fibre reinforced polymers (GFRPs) have been widely used as one of the main electrical insulating structures for superconducting magnets. A new type of GFRP insulation material using cyanate ester/epoxy resin as a matrix was developed in this study, and the samples were irradiated by Co-60 for 1 MGy and 5 MGy dose. Space charge distributed within the sample were tested using the pulsed electroacoustic method, and charge concentration was found at the interfaces between glass fibre and epoxy resin. Thermally stimulated current (TSC) and dc conduction current were also tested to evaluate the irradiation effect. It was supposed that charge mobility and density were suppressed at the beginning due to the crosslinking reaction, and for a higher irradiation dose, molecular chain degradation dominated and led to more sever space charge accumulation at interfaces which enhance the internal electric field higher than the external field, and transition field for conduction current was also decreased by irradiation. Space charge dynamic at cryogenic temperature was revealed by conduction current and TSC, and space charge injection was observed for the irradiated samples at 225 K, which was more obvious for the irradiated samples.

Effect of gamma irradiation on quality of dried potato

International Nuclear Information System (INIS)

Wang, J.; Chao, Y.

2003-01-01

The objectives of this study were to obtain the effect of gamma irradiation on the quality of dried potato. Experiments were conducted to study the influence of different doses, air temperatures, slice thickness of potatoes on the dehydration rate, appearance quality (L-values), vitamin C content, and the rehydration ratio of dried potatoes. The greater the dose, the higher the dehydration rate, the lesser the vitamin C content, and the lower the rehydration ratio. The L-values for low-dose irradiation was greater than that for non-irradiated potatoes

Effect of gamma irradiation on quality of dried potato

Energy Technology Data Exchange (ETDEWEB)

Wang, J. E-mail: jwang@zju.edu.cn; Chao, Y

2003-03-01

The objectives of this study were to obtain the effect of gamma irradiation on the quality of dried potato. Experiments were conducted to study the influence of different doses, air temperatures, slice thickness of potatoes on the dehydration rate, appearance quality (L-values), vitamin C content, and the rehydration ratio of dried potatoes. The greater the dose, the higher the dehydration rate, the lesser the vitamin C content, and the lower the rehydration ratio. The L-values for low-dose irradiation was greater than that for non-irradiated potatoes.

A history of studies on safety of irradiated foods

International Nuclear Information System (INIS)

Miyahara, Makoto

2003-01-01

This report explained a history of studies on safety of irradiated foods in the United States. The army of USA had begun an experiment of irradiated foods in 1953. The toxic tests consisted of three phase, the phase I (1954 to 1959), phase II (1956 to 1965) and phase III (1971 to 1978). In the phase I, the short period toxic tests (90days) of 54 kinds of foods were carried out using high and low irradiation. The Swift and Company Laboratories reported detailed animal tests of 2685 albino rat, chickens and human. The animal tests showed many kinds of nutrition disorder, but the human test no problem. On phase II, 22 kinds of foods were tested for long period using rat, dog and mouse. Dog showed many kinds of symptom, for example, low birthrate, short life time, low growth rate, increasing spleen weight and thyroid disease. On phase III, two companies carried out the toxic test and Ralston Purina Company report is only data to be used now. Atomic Energy Commission (AEC) (1960 to 1970), Department of Commerce (1965 to 1976) and Department of Agriculture (1961 to 1966) studied safety of irradiated foods. Food and Drug Administration (FDA) determined that the irradiated foods belonged to under the category of food additive in 1958. FDA tests safety of irradiated foods using the determination tree and permitted many kinds of irradiated foods. (S.Y.)

Physic-chemical Study of Starch Extracted from Irradiated Corn Flour

International Nuclear Information System (INIS)

Pozo Sanchez, R. del; Alvarez Gil, M.

1986-01-01

The effects of gamma irradiation on starch extracted from irradiated samples of corn flour were studied in the range 0,6 kGy-1,0 kGy. Amylographic properties, solubility and swelling powder of starch samples were determined immediately after irradiation and at 75 days storage at environment conditions (16 0 C-31 0 C, 55%-97% H.R.). Diffraction patterns of crystalline starch were also obtained by X-rays. Gelatinization temperature, swelling powder and diffraction patterns did not change upon irradiation, but a decrease in viscosity and an increase in starch solubility were observed within the dose-range and storage time studied. (author)

Study on irradiation treatment to drunk crab

International Nuclear Information System (INIS)

Cao Hong; Chen Xiulan; Zhai Jianqing; Bao Jianzhong; Wang Jinrong

2002-01-01

For guaranteeing the quality of irradiated drunk crab, manufacture method of the dosimeter, sample setting and taking position, irradiation time, asymmetry degree of irradiation dose, contrast of the dosimeter are discussed and some reference datum to commercialization of drunk crab's irradiation are provided

Conductivity change of defective graphene by helium ion beams

Directory of Open Access Journals (Sweden)

Yuichi Naitou

2017-04-01

Full Text Available Applying a recently developed helium ion microscope, we demonstrated direct nano-patterning and Anderson localization of single-layer graphene (SLG on SiO2/Si substrates. In this study, we clarified the spatial-resolution-limitation factor of direct nano-patterning of SLG. Analysis of scanning capacitance microscopy measurements reveals that the conductivity of helium ion (H+-irradiated SLG nanostructures depends on their geometrical size, i.e., the smaller the H+-irradiated SLG region, the higher its conductivity becomes. This finding can be explained by the hopping carrier transport across strongly localized states of defective SLG.

Preliminary study on irradiation breeding of ornamental lotus

International Nuclear Information System (INIS)

Chen Xiulan; Bao Jianzhong; Liu Chungui; Cao Hong; Zhai Jianqing

2004-01-01

The effects of γ-ray irradiation on seeds and stems of ornamental lotus were studied. The results show that the mutation rate of seeds is higher than that of stems, and 30-60 Gy is the appropriate irradiation dose. The varieties with red or multi-color flower are more mutable than those with white flower. Two varieties were selected

Studies on Post-Irradiation DNA Degradation in Micrococcus Radiodurans, Strain RII51

DEFF Research Database (Denmark)

Auda, H.; Emborg, C.

1973-01-01

The influence of irradiation condition on post-irradiation DNA degradation was studied in a radiation resistant mutant of M. radiodurans, strain ${\\rm R}_{{\\rm II}}5$. After irradiation with 1 Mrad or higher more DNA is degraded in cells irradiated in wet condition than in cells irradiated with t...

Study of irradiated F82H steel and its model Fe-Cr alloy by Moessbauer spectroscopy

International Nuclear Information System (INIS)

Huang, S.S.; Kitao, S.; Xu, Q.; Sato, K.; Yoshiie, T.

2013-01-01

In this work, Moessbauer spectroscopy which is a super-precision tool was conducted on F82H and its model Fe-Cr alloys before and after irradiation to take a further look on the interaction between carbides and point defects and Cr effect on microstructural evolution during irradiation in void incubation period. (J.P.N.)

EPR study on gamma-irradiated fruits dehydrated via osmosis

Energy Technology Data Exchange (ETDEWEB)

Yordanov, N.D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)]. E-mail: ndyepr@bas.bg; Aleksieva, K. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

2007-06-15

The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and {gamma}-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas {gamma}-irradiated exhibit 'sugar-like' EPR spectra. The recorded EPR spectra are monitored for a period of 7 months after irradiation (stored at low humidity and in the dark). The results suggest longer period of unambiguous identification of the radiation processing of osmose dehydrated fruits. Therefore, the Protocol EN 13708,2001 issued by CEN is fully applicable for the studied fruit samples.

Effect of irradiation on the tensile properties of niobium-base alloys

International Nuclear Information System (INIS)

Grossbeck, M.L.; Heestand, R.L.; Atkin, S.D.

1986-11-01

The alloys Nb-1Zr and PWC-11 (Nb-1Zr-0.1C) were selected as prime candidate alloys for the SP-100 reactor. Since the mechanical properties of niobium alloys irradiated to end-of-life exposure levels of about 2 x 10 26 neutrons/m 2 (E > 0.1 MeV) at temperatures above 1300 K were not available, an irradiation experiment (B-350) in EBR-II was conducted. Irradiation creep, impact properties, bending fatigue, and tensile properties were investigated; however, only tensile properties will be reported in this paper. The tensile properties were studied since they easily reveal the common irradiation phenomena of hardening and embrittlement. Most attention was directed to testing at the irradiation temperature. Further testing was conducted at lower temperatures in order to scope the behavior of the alloys in cooldown conditions

Study on innocent irradiation treatment of Trichinella spiralis pork

International Nuclear Information System (INIS)

Zhao Guang; Guo Anxi; Xu Zhaomei

1992-01-01

The effects of 60 Co gamma rays on pork Trichinella spiralis and nutritional hygiene evaluation of irradiated Trichinella spiralis pork were studied by using animal infestation test and artificial gastric juice digestion method. The results showed that when mouse was infested by Trichinella spiralis pork irradiated with a dose of 0.04 kGy, the number of the second generation larvae and the parasitism in the muscle were reduced. 0.08 kGy irradiation could render the intestine Trichinella spiralis sterile. 0.1 kGy blocked the growth of Trichinella spiralis, which were excreted from the body four days after infestation. 0.2-0.8 kGy irradiation could severely block the growth of Trichinella spiralis, which were excreted completely from the body within forth-eight hours when irradiated with 7 kGy and 8 kGy, the Trichinella spiralis body was not found in the intestine within twenty-four hours. 0.3 kGy and 1 kGy irradiation had no harmful effect on nutrition and wholesomeness of Trichinella spiralis pork. Innocent irradiation treatment of Trichinella spiralis pork is practicable, and the lowest dose should be 0.3 kGy

Prospective study of nutritional support during pelvic irradiation

International Nuclear Information System (INIS)

Kinsella, T.J.; Malcolm, A.W.; Bothe, A. Jr.; Valerio, D.; Blackburn, G.L.

1981-01-01

A prospective study of nutritional support during pelvic irradiation was carried out in 32 patients with a primary pelvic malignancy and prior weight loss. Both curative and palliative patients were eligible for the study. Seventeen patients were randomized to receive intravenous hyperalimentation (IVH) and fifteen patients served as controls who were maintained on their regular diet. Patients were stratified by percent body weight loss. Tolerance to therapy was assessed by evaluation of functional status and by using nutritional parameters of body weight change, change in serum protein levels, and response to delayed hypersensitivity skin tests. The curative IVH group tolerated therapy well by both functional and nutritional measurements. All curative IVH patients completed the planned radiation therapy without a treatment break and were fully active following treatment. Patients gained an average of 4.0 kg body weight during irradiation, which was significantly different from the curative control patients. They demonstrated a significant increase in serum transferrin reflecting an improvement in visceral protein. In addition, all showed a positive response to delayed hypersensitivity skin tests at the completion of irradiation. The palliative IVH patients often did poorly because of progression of disease and demonstrated only an elevation of serum transferrin during treatment. The results in the curative IVH group suggest a potential adjunctive role for intravenous hyperalimentation in the malnourished cancer patient undergoing pelvic irradiation. Clearly, further study of nutritional support during pelvic irradiation is needed using curative patients with a single tumor type and significant prior weight loss

Study on identification of irradiated food containing cellulose by ESR

International Nuclear Information System (INIS)

Wan Xiaojuan; Dou Daying; Xu Gang; Jiao Zheng; Wang Jia; Zheng Jianfei; Jiao Zheng; Wu Minghong; Ding Guoji

2008-01-01

The fast development and application of food irradiation technology signify the necessity and urgency to research on effective detection method for irradiated food. In this paper, we report a preliminary study in this area with dried chili powder, peanuts and strawberry seeds. The food samples were irradiated to 0.5, 1.0, 3.0, 5.0 and 10.0 kGy by 60 Co gamma rays. The relation between ESR intensity and irradiation dose, and correlation R 2 , were studied. The results showed that the ESR signal intensity is positively related with the dose. ESR intensity of the strawberry increased the slowest with the dose, and the chili powder had the most accurate calculation. Accurate dose-effect curves, however, require repeating tests and further studies are needed to verify the ESR results. (authors)

An ESR study of radicals induced in irradiated fresh mango

International Nuclear Information System (INIS)

Kikuchi, Masahiro; Hussain, Mohammed S.; Morishita, Norio; Kobayashi, Yasuhiko; Ukai, Mitsuko; Shimoyama, Yuhei

2009-01-01

An electron spin resonance (ESR) spectroscopic study was performed on the radicals induced irradiated fresh mangoes. Fresh Philippine mangoes were irradiated by the γ-rays, lyophilized and powdered. The ESR spectrum of the dry specimen showed a strong main peak at g=2.004 and a pair of peaks at both magnetic fields of the main peak. The main peak detected from flesh and skin specimens faded away in a few days after the irradiation. On the other hand, the side peaks showed a well-defined dose response even 9 days after the irradiation. The side-peak is a useful mean to define the irradiation on fresh mangoes. (author)

Chemical changes in food packaging resulting from ionizing irradiation

International Nuclear Information System (INIS)

Thayer, D.W.

1988-01-01

Recent approvals of food irradiation processes by the U.S. Food and Drug Administration have led to a search for packaging approved for use with ionizing radiation. Though 13 packaging materials were approved several years ago as food contactants for gamma irradiation up to 10 kGy at refrigeration temperatures and 4 packaging materials were approved for up to 60 kGy at cryogenic temperatures, no currently used packaging is approved for irradiated foods. Extensive research was conducted by the U.S. Army and others on the suitability of both flexible packaging and metal cans for packaging irradiated foods. The results of the studies of packaging for irradiated foods will be described and discussed in context of currently used packaging materials for non-irradiated meats and poultry

Plant responses to UV-B irradiation are modified by UV-A irradiation

International Nuclear Information System (INIS)

Middleton, E.M.; Teramura, A.H.

1993-01-01

The increasing UV-B radiation (0.28-0.32 μm) reaching the earth's surface is an important concern. Plant response in artificial UV-B irradiation studies has been difficult to assess, especially regarding photosynthetic pigments, because the fluorescent lamps also produce UV-A (0.32-0.40μm) radiation which is involved with blue light in pigment synthesis. Both UV-A and UV-B irradiances were controlled in two glasshouse experiments conducted under relatively high PPFD (> 1300μmol m -2 s -1 ) at two biologically effective daily UV-B irradiances (10.7 and 14.1 kJ m -2 ); UV-A irradiances were matched in Controls (∼5, 9 kJ m -2 ). Normal, chlorophyll-deficient, and flavonoid-deficient isolines of soybean cultivar, Clark, were utilized. Many growth/ pigment variables exhibited a statistically significant interaction between light quality and quantity: in general, UV-A radiation moderated the damaging effects of UV-B radiation. Regression analyses demonstrated that a single negative function related photosynthetic efficiency to carotenoid Content (r 2 =0.73, P≤0.001), implying a open-quotes costclose quotes in maintaining carotenoids for photoprotection. A stomatal limitation to photosynthesis was verified and carotenoid content was correlated with UV-B absorbing compound levels, in UV-B irradiated plants

Food Irradiation Technology in the Philippines

International Nuclear Information System (INIS)

De Guzman, Zenaida M.

2015-01-01

The applications of ionizing radiation for the preservation of food and agricultural products by delaying ripening, destruction of insect pests and pathogenic microorganisms have shown great promise in the country. For more than 30 years, the Philippine Nuclear Research Institute (PNRI) in collaboration with other government and private sectors, has undertaken research and development studies and pilot and semi-commercial scale irradiation of foods. Some of the foods found to be benefit from the use of irradiation technology are mangoes and papayas for disinfestations and delay ripening; onions and garlic for inhibition of sprouting; spices and dehydrated products for reduction of microbial growth and rice and corn for insect and shelf-life extension. Two regulations approved by the Department of Health and the Bureau of Plant Industry are in place creating an enabling environment for food safety and trade of irradiated food. The conduct of awareness program in various parts of the country provided knowledge and information about the food irradiation technology. The Institute has been part of the international projects (IAEA and USDA) on the use of irradiation for sanity and phytosanitary treatment of food. The projects not only established the potential benefits of food irradiation for socio-economic development of the country but also built considerable capacity to properly treat foods. Some of the recent developments in the area of food irradiation include publication of Philippine National Standard (PNS) on Food Irradiation: Code of Good Irradiation Practices which will serve as a guide for stakeholders to irradiate food, a newly-established Electron Beam Facility to demonstrate the potential use of EB and a feasibility study of putting-up a commercial irradiation facility in the country. (author)

Effect of UV irradiation on aflatoxin reduction: a cytotoxicity evaluation study using human hepatoma cell line.

Science.gov (United States)

Patras, Ankit; Julakanti, Sharath; Yannam, Sudheer; Bansode, Rishipal R; Burns, Mallory; Vergne, Matthew J

2017-11-01

In this proof-of-concept study, the efficacy of a medium-pressure UV (MPUV) lamp source to reduce the concentrations of aflatoxin B 1 , aflatoxin B 2 , and aflatoxin G 1 (AFB 1, AFB 2 , and AFG 1 ) in pure water is investigated. Irradiation experiments were conducted using a collimated beam system operating between 200 to 360 nm. The optical absorbance of the solution and the irradiance of the lamp are considered in calculating the average fluence rate. Based on these factors, the UV dose was quantified as a product of average fluence rate and treatment time. Known concentrations of aflatoxins were spiked in water and irradiated at UV doses ranging from 0, 1.22, 2.44, 3.66, and 4.88 J cm -2 . The concentration of aflatoxins was determined by HPLC with fluorescence detection. LC-MS/MS product ion scans were used to identify and semi-quantify degraded products of AFB 1 , AFB 2 , and AFG 1 . It was observed that UV irradiation significantly reduced aflatoxins in pure water (p UV light may have caused photolysis of AFB 1 , AFB 2 , and AFG 1 molecules. In cell culture studies, our results demonstrated that the increase of UV dosage decreased the aflatoxin-induced cytotoxicity in HepG 2 cells. Therefore, our research finding suggests that UV irradiation can be used as an effective technique for the reduction of aflatoxins.

Synthetic study of reactor irradiation for medical use

International Nuclear Information System (INIS)

An, Shigehiro; Furuhashi, Akira; Kanda, Keiji; Sumita, Kenji; Kakihana, Hidetake.

1978-01-01

This report is described on the results of the study on the reactor irradiation for medical use shared by the Nuclear Engineering Research Laboratory, Faculty of Engineering, University of Tokyo, and other seventeen facilities. Boron neutron-capturing therapy developed in Japan is extremely significant treating method for tumors by destroying tumor cells of encephaloma, etc. selectively. This is the synthetic study for promoting the above therapeutic method. Two existing reactors were reconstructed into the thermal neutron reactors for boron neutron-capturing therapy. The various preparatory and physical researches were made with the reconstruction, and the therapy was tried on eleven cases. Further experiments were made on the following points: (1) To promote treatment on encephaloma by boron neutron-capturing therapy. (2) To develop its application to malignant tumors other than encephaloma. (3) Animal irradiation experiments. (4) The basic experiments on the cellular level. (5) The study of remote controlled anesthesia. (6) To control irradiated dose. (7) To improve boron compounds. (8) To condense radioisotopes. (Kobatake, H.)

Renal effects of renal x irradiation and induced autoallergic glomerulonephritis

International Nuclear Information System (INIS)

Rappaport, D.S.; Casarett, G.W.

1979-01-01

This study was conducted to determine what influence a single large x-ray exposure of kidney has on the development and course of an experimental autoallergic glomerulonephritis (EAG) in rats. EAG was induced in female Sprague-Dawley rats by immunization with Bordetella pertussis vaccine and homogenate of homologous kidney tissue and Freund's complete adjuvant. Progressive arteriolonephrosclerosis (ANS) was observed in right (irradiated) kidneys following unilateral renal irradiation (1500 rad). Rats were either immunized, sham-immunized, irradiated, sham-irradiated, or both immunized and irradiated. Light and immunofluorescent microscopic observation, urine protein content, and kidney weights were evaluated. In immunized-irradiated animals the effects of irradiation and immunization were largely additive. Immunization did not considerably influence the development and course of ANS and irradiation did not considerably influence the development and course of EAG

Color formation study of irradiated polymers by electron beam

International Nuclear Information System (INIS)

Nardi, Daniela Teves

2004-01-01

Color formation on national and commercial polymers (polymethyl methacrylate, polystyrene and polycarbonate) irradiated by electrons beam was investigated by colorimetry (CIELab), electron spectroscopy resonance (ESR), photoacoustic infrared spectroscopy (FTIR-PAS) and differential exploratory calorimetry (DSC). The heat effect on colorimetric properties was investigated after heating (110 deg C for 1 hour) of irradiated polymers at 150 kGy. The rule of oxygen in colorimetric properties of irradiated polycarbonate was investigated in the air presence and absence (p = 10 -3 mmHg). The visual aspect did not agree with colorimetric parameters only for polycarbonate. Yellow color and darkness were induced by radiation for all studied polymers varying only the intensity and behavior in function of post-irradiation time and heating. Polymethyl methacrylate and polystyrene ESR spectra showed that radicals could be responsible by yellow color centers. Wherever, in polycarbonate, color centers were not due radical species. The nature of color centers for any studied polymer was not study by FTIR-PAS because there were no changes in FTIR-PAS spectra neither in function of dose nor heating. Polycarbonate was the most radiosensible and polystyrene was the most radioresistant of all studied polymers in concern of colorimetric properties. (author)

Structural and functional changes in the intenstine of irradiated and hypothermic irradiated rats : a scanning and transmission electron microscopic study

International Nuclear Information System (INIS)

Chaudhuri, S.; Chaudhuri, Swapna; Roy, Bijon

1982-01-01

Severe destructive changes in the intestine of rats following whole body exposure to gamma rays (832 rads) were observed by light microscope, scanning and transmission electron microscope studies. Hypothermia (15deg C rectal temperature) induced prior to irradiation protected the intestinal mucosa from destruction. A simultaneous study showed that glucose absorption decreased significantly in irradiated rats, whereas it was increased in hypothermic irradiated animals. (author)

Health protection and food preservation by gamma irradiation

Science.gov (United States)

1976-01-01

Results of several major studies on food systems for space missions beginning with Apollo 12 through Apollo-Soyuz and investigations of the application of irradiation to food for manned space flight are reported. The study of flight food systems involved the application of radurization (pasteurizing levels) doses of gamma irradiation to flour and bread supplied by Pepperidge Farms in advance of the missions. All flights from Apollo 12 through 17 carried irradiated fresh bread. On Apollo 17, cooperation with Natick Laboratories permitted the introduction of a ham sandwich using irradiated bread and irradiated sterile ham. Investigations centered on irradiated bread were conducted during the course of these missions. Studies were applied to the concept of improving fresh bread from the point of view of mold inhibition. The studies considered how irradiation could best be applied at what levels and on a variety of bread types. Throughout the studies of the application of gamma irradiation the emphasis was placed upon using low levels of irradiation in the pasteurizing or radurizing doses--under a Megarad. The primary goal was to determine if a public health benefit could be demonstrated using radurization along with food preservation and food quality improvements. The public health benefit would be parallel to that of pasteurization of milk as a concept. Publications are included providing the details of these observations, one dealing with the flour characteristics and the other dealing with the influence on fresh bread types. These demonstrate the major findings noted during the period of the studies examining bread.

75 MeV boron ion irradiation studies on Si PIN photodiodes

Energy Technology Data Exchange (ETDEWEB)

Prabhakara Rao, Y.P.; Praveen, K.C. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570006 (India); Rejeena Rani, Y. [Integrated Circuits Division, Bharat Electronics Limited, Bangalore 560013, Karnataka (India); Tripathi, Ambuj [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Gnana Prakash, A.P., E-mail: gnanap@hotmail.com [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570006 (India)

2013-12-01

The highly sensitive silicon PIN photodiodes were fabricated to use in radiation environments. The Si PIN photodiodes are coated with 150 nm silicon dioxide (SiO{sub 2}) as anti-reflective (AR) coating. The presence of AR coating on the performance of irradiated PIN photodiodes is studied up to a total dose of 10 Mrad. The effects of 75 MeV boron (B{sup 5+}) ions and {sup 60}Co gamma radiation on the I–V, C–V and spectral responses of PIN photodiodes were studied systematically to understand the radiation tolerance of the devices. The 75 MeV B{sup 5+} irradiation results are compared with {sup 60}Co gamma irradiated results in the same dose range for 1 mm × 1 mm and 10 mm × 10 mm active area PIN photodiodes. The irradiation results show that the ion irradiated PIN photodiodes show more degradation when compared {sup 60}Co gamma irradiated devices. The irradiation results are presented in this paper and the possible mechanism behind the degradation of photodiodes is also discussed in the paper.

Electrical properties of irradiated PVA film by using ion/electron beam

Science.gov (United States)

Abdelrahman, M. M.; Osman, M.; Hashhash, A.

2016-02-01

Ion/electron beam bombardment has shown great potential for improving the surface properties of polymers. Low-energy charged (ion/electron) beam irradiation of polymers is a good technique to modify properties such as electrical conductivity, structural behavior, and their mechanical properties. This paper reports on the effect of nitrogen and electron beam irradiation on the electrical properties of polyvinyl alcohol (PVA) films. PVA films of 4 mm were exposed to a charged (ion/electron) beam for different treatment times (15, 30, and 60 minutes); the beam was produced from a dual beam source using nitrogen gas with the other ion/electron source parameters optimized. The dielectric loss tangent tan δ , electrical conductivity σ , and dielectric constant ɛ ^' } in the frequency range 100 Hz-100 kHz were measured at room temperature. The variation of dielectric constant and loss tangent as a function of frequency was also studied at room temperature. The dielectric constant was found to be strongly dependent on frequency for both ion and electron beam irradiation doses. The real (ɛ ^' }) and imaginary (ɛ ^' ' }) parts of the dielectric constant decreased with frequency for all irradiated and non-irradiated samples. The AC conductivity showed an increase with frequency for all samples under the influence of both ion and electron irradiation for different times. Photoluminescence (PL) spectral changes were also studied. The formation of clusters and defects (which serve as non-radiative centers on the polymer surface) is confirmed by the decrease in the PL intensity.

Simple Moving Voltage Average Incremental Conductance MPPT Technique with Direct Control Method under Nonuniform Solar Irradiance Conditions

Directory of Open Access Journals (Sweden)

Amjad Ali

2015-01-01

Full Text Available A new simple moving voltage average (SMVA technique with fixed step direct control incremental conductance method is introduced to reduce solar photovoltaic voltage (VPV oscillation under nonuniform solar irradiation conditions. To evaluate and validate the performance of the proposed SMVA method in comparison with the conventional fixed step direct control incremental conductance method under extreme conditions, different scenarios were simulated. Simulation results show that in most cases SMVA gives better results with more stability as compared to traditional fixed step direct control INC with faster tracking system along with reduction in sustained oscillations and possesses fast steady state response and robustness. The steady state oscillations are almost eliminated because of extremely small dP/dV around maximum power (MP, which verify that the proposed method is suitable for standalone PV system under extreme weather conditions not only in terms of bus voltage stability but also in overall system efficiency.

Development of Schistosoma incognitum in mice upon intraperitoneal inoculation with irradiated schistosomula

International Nuclear Information System (INIS)

Bhilegaonkar, N.G.; Sahasrabudhe, V.K.

1987-01-01

As a prelude to the study of the immunizing potential of gamma-irradiated Schistosoma incognitum schistosomula, experiments were conducted to study the effect of different doses of gamma irradiation (1,3,5 and 10 kr) on the development and survival of S. incognitum in mice, and its attendant pathology. The present experiments suggested that 3 and 5 kr irradiation doses can be safely used for irradiating schistosomula for immunization experiments in mice as the worms will not mature and therefore no harm will be caused which is mainly due to the eggs. (author). 7 refs

Application of irradiation techniques to food and foodstuffs

International Nuclear Information System (INIS)

Kwon, Joong Ho; Byun, Myung Woo; Kim, Suc Won; Yang, Jae Seung; Cho, Han Ok

1991-02-01

A preservation study of dried fish, anchovies, has been conducted to determine the effect of gamma irradiation and laminated(nylon/polyethylene) film packaging on microbiological, physicochemical and organoleptic qualities of stored samples under room, refrigeration and freezing temperatures. Irradiation at less than 5 kGy and NY/PE-laminated film packaging are anticipated to be significantly effective for over 10 months in terms of improving the hygienic quality and extending the storage life of boiled-dried anchovies. In a survey participating 700 consumers, respondents preferred irradiated food to chemically-treated one. However, majority of respondents (55.7 %) was ignorant of the fact that the Korean government and international organizations concerned have approved the wholesomeness of irradiated food. Insufficiency of public information and understanding for irradiated food was indicated as a major cause for retardation of commercial utilization of food irradiation technology. In a response concerning perception and acceptance toward irradiated food, there was a significant difference between radiation worker and the general public. (Author)

Gamma irradiation effect on polymers derived of pyrrole synthesized by plasma

International Nuclear Information System (INIS)

Lopez G, O. G.

2013-01-01

This work studies the effect of gamma irradiation at doses of 50, 100, 200, 400 and 800 kGy on polymers obtained from pyrrole synthesized by plasma. The evolution of the structure was studied by Fourier transform infrared spectroscopy (Ftir) and X-ray photoelectron spectroscopy (XPS). The Ftir spectra show that poly pyrroles have N-H, C-H, C=O, triple and consecutive double bonds in their structure. The irradiated polymers show the same chemical groups in their structure without significant changes. Nevertheless, a more detailed analysis by XPS allows the identification of superficial chemical states, such as: C=CH-C, C=CC-C, C-NH-C, C-NC-C, etc., and shows that most of these states are present in all polymers but with different participation. One possible mechanism indicates that as the irradiation dose increases, dehydrogenation processes are performed increasing fragmentation, crosslinking and formation of multiple bonds. The fragmentation and thermal degradation were studied by thermogravimetric analysis, indicating that the loss of moisture and light compounds formed during gamma irradiation occurs in the firsts 100 grades C. The main degradation of all polymers occurs from 150 to 700 grades C, suggesting that the thermal stability is independent of the irradiation dose in the interval studied. Morphology was studied using scanning electron microscopy techniques. Before irradiation, the polymer presented a uniform and practically smooth surface, however, after gamma irradiation, the applied energy increased roughness and macro fragmentation. The roughness and functional groups on the surface reduced the contact angle with water as the irradiation dose increased. However, the polymers are hydrophilic, because for all doses that contact angle is smaller than 90 grades C. Electrical conductivity was calculated respect to temperature in the interval from 25 to 100 grades C. Conductivity increases with temperature and is slightly greater in the irradiated polymers

Effects on storage life and quality of irradiated mangoes

International Nuclear Information System (INIS)

Pongsuwan, Dara; Therapawa, Wallapa; Akawassapong, Pakinee; Jattanajet, Jumlong.

1982-01-01

Investigations on the effect of irradiation at 50 Krad, hot water treatment at 55 degC 5 min and hot water treatment followed by irradiation were carried out on the mature green Keaw mango to eradicate anthracnose disease development and delay ripening. Before introducing all treatments, mangoes were inoculated by Colletotrichum gloeosporioides. All samples were determined after stored at 10 +- 2 degC and at 85% RH for 3 weeks. No difference in disease control between untreated and irradiated batches, but fruits treated with hot water followed by irradiation were significantly different from untreated ones. All treatments were effective in delaying ripening. Higher dosage of irradiation with a combination of hot water treatment was studied on colour break Pimsen Prure mango and 75 Krad after hot water treatment proved to be promising. Further study is being conducted

Preliminary calculations of stress change of fuel pin using SiC/SiC composites for GFR with changing of thermal conductivity degradation by irradiation

International Nuclear Information System (INIS)

Lee, J. K.; Naganuma, M.

2006-01-01

Gas cooled Fast Reactor (GFR) is being researched as a candidate concept of Generation IV international Forum. As a main feature of GFR, it should be maintained high temperature and pressure of coolant gas for heat transfer efficiency. Such a demanding environment requires high-temperature-resistant structural materials distinguished from traditional steel material. Consequently, ceramics are promising candidate material of core components. Especially, Silicon Carbide fiber reinforced Silicon Carbide composites (SiC/SiC) have encouraging characteristics such as refractoriness, low activation and toughness. Application of new material to core components must be explained by the viewpoint of engineering validity. Therefore, present study surveyed that current report for mechanical strength and thermal conductivity of SiC/SiC composites. According to the reports, neutron irradiation environment degraded mechanical properties of SiC/SiC composites. To confirm applicability to core components, model of fuel pin using SiC/SiC composites was assumed with feasible mechanical properties. Furthermore, it was calculated and estimated that the stress caused by temperature variation of inner and outer side of assumed model of cladding tube. Stress was calculated by changing of input date such as thickness of cladding tube, temperature variation, thermal conductivity and linear power. In the range of this study, the most important factor was identified as degradation of thermal conductivity by irradiation. It caused a significant stress and limited a geometrical design of fuel pin. It was discussed that the differences of heat transfer between isotropic and anisotropic materials like a metal and composites. These results should be helpful not only to determine a design factor of core component but also to indicate an improvement direction of SiC/SiC composites. Through these work, reliability and safety of GFR will be increased

Thermogravimetric study of γ-irradiated lanthanum oxalate

International Nuclear Information System (INIS)

Nayak, H.; Bhatta, D.

2000-01-01

Thermogravimetric study of La 2 (C 2 O 4 ) 3 , exposed to different doses (5.0 - 50.0 x 10 -2 MGy) of γ-rays has been carried out. Marginal effect is observed at lower doses which is prominent at higher dose (5.0 x 10 -1 MGy). The radiolytic damaged entities, generated by irradiation favours the reaction by creating new potential nucleation centres in the lattice. The solid product, La 2 O 3 formed by irradiation also acts as a heterogeneous catalyst and brings out changes in the reactivity of the solid. (author)

A Review on Microbial Mutagenesis through Gamma Irradiation for Agricultural Applications

International Nuclear Information System (INIS)

Hoe, P.C.K.; Khairuddin Abdul Rahim

2016-01-01

Gamma irradiation is widely used in sterilization and mutagenesis, especially for plant breeding and crop protection. Microbial mutagenesis through gamma irradiation is mainly applied in fermentation industry. In agriculture, gamma irradiation is mostly applied in crop improvement. Microbial mutagenesis is mainly applied against fungus and spore-forming bacteria, which are resistant to gamma irradiation. Response of microbes to gamma irradiation varies and depends on various factors. Review of previous works on gamma irradiation for microbial mutagenesis in agriculture may provide some information for the use of this method. The general view on gamma irradiation, its application, and mutagenesis are discussed in this paper. Further investigation on microbial mutagenesis should consider molecular changes, information on which is lacking in previous works. Moreover, studies on microbial mutagenesis are still lacking in Malaysia despite having several gamma irradiation facilities. Therefore, further studies on microbial mutagenesis should be conducted. (author)

Economic Feasibility Study for Using Irradiation Technology in Preservation of Animalism Foods

International Nuclear Information System (INIS)

El Gameel, E.A.

2011-01-01

The present study discus the economic feasibility for the preservation animalism foods by using irradiation technology. This study has included the technical data, regression foretelling for the throughput, determination of irradiators types and radiation sources activity. This study comprises the financial analysis for the establishment animalism foods irradiation facilities (types: tote box, pallet conveyor) and the national return

Study on process control and acceptability of irradiated seasonings

International Nuclear Information System (INIS)

Chen Qixun; Xu Peishu; Chen Hao; Chen Lihua; Dong Shaobin

1993-01-01

This paper studied the process control and quality control of irradiated seasonings for commercial purposes, market test and consumers' acceptability. The results showed that the rate of relative deviation of dose was less than 2 and the uniformity was better than 1.31 and the number of microbes decreased by 3-4 orders of magnitude after treatment with 8 kGy. No pathogenic bacteria were discovered and sensory evaluation as well as quality analysis were not changed. 110 tons of irradiated seasonings have been supplied to domestic markets and stores since 1990. The statistic data of 2045 consumers investigated showed that 67% of consumers heard about food irradiation. 72% of persons and 67% of families were willing to buy irradiated seasonings. (author)

Gamma irradiation reduces the immunological toxicity of doxorubicin, anticancer drug

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae-Hun; Sung, Nak-Yun; Raghavendran, H. Balaji; Yoon, Yohan; Song, Beom-Seok; Choi, Jong-il [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Yoo, Young-Choon [Department of Microbiology, College of Medicine, Konyang University, Daejeon 302-718 (Korea, Republic of); Byun, Myung-Woo [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Hwang, Young-Jeong [Division of Food Science, International University of Korea, Jinju 660-759 (Korea, Republic of); Lee, Ju-Woon [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of)], E-mail: sjwlee@kaeri.re.kr

2009-07-15

Doxorubicin (DOX) is a widely used anticancer agent, but exhibits some immunological toxicity to patients during chemotherapy. The present study was conducted to evaluate the effect of gamma irradiation on the immunological response and the inhibition activity on in vivo tumor mass of DOX. The results showed that DOX irradiated at 10 and 20 kGy reduce the inhibition of mouse peritoneal macrophage proliferation and induce the release of cytokines (TNF-{alpha} and IL-6) when compared with non-irradiated DOX. The cytotoxicity against human breast (MCF-7), murine colon adenocarcinoma (Colon 26) and human monocytic (THP-1) tumor cell were not significantly different between non-irradiated and irradiated DOX (P<0.05). In vivo study on the tumor mass inhibition, gamma-irradiated DOX showed a considerable inhibition of tumor mass and this effect was statistically non-significant as compared with non-irradiated DOX. In conclusion, gamma irradiation could be regarded as a potential method for reducing the immunological toxicity of DOX. Further researches is needed to reveal the formation and activity of radiolysis products by gamma irradiation.

Gamma irradiation reduces the immunological toxicity of doxorubicin, anticancer drug

International Nuclear Information System (INIS)

Kim, Jae-Hun; Sung, Nak-Yun; Raghavendran, H. Balaji; Yoon, Yohan; Song, Beom-Seok; Choi, Jong-il; Yoo, Young-Choon; Byun, Myung-Woo; Hwang, Young-Jeong; Lee, Ju-Woon

2009-01-01

Doxorubicin (DOX) is a widely used anticancer agent, but exhibits some immunological toxicity to patients during chemotherapy. The present study was conducted to evaluate the effect of gamma irradiation on the immunological response and the inhibition activity on in vivo tumor mass of DOX. The results showed that DOX irradiated at 10 and 20 kGy reduce the inhibition of mouse peritoneal macrophage proliferation and induce the release of cytokines (TNF-α and IL-6) when compared with non-irradiated DOX. The cytotoxicity against human breast (MCF-7), murine colon adenocarcinoma (Colon 26) and human monocytic (THP-1) tumor cell were not significantly different between non-irradiated and irradiated DOX (P<0.05). In vivo study on the tumor mass inhibition, gamma-irradiated DOX showed a considerable inhibition of tumor mass and this effect was statistically non-significant as compared with non-irradiated DOX. In conclusion, gamma irradiation could be regarded as a potential method for reducing the immunological toxicity of DOX. Further researches is needed to reveal the formation and activity of radiolysis products by gamma irradiation.

Preliminary irradiation test results from the Yankee Atomic Electric Company reactor vessel test irradiation program

International Nuclear Information System (INIS)

Biemiller, E.C.; Fyfitch, S.; Campbell, C.A.

1993-01-01

The Yankee Atomic Electric Company test irradiation program was implemented to characterize the irradiation response of representative Yankee Rowe reactor vessel beltline plate materials and to remove uncertainties in the analysis of existing irradiation data on the Yankee Rowe reactor vessel steel. Plate materials each containing 0.24 w/o copper, but different nickel contents at 0.63 w/o and 0.19 w/o, were heat treated to simulate the Yankee vessel heat treatment (austenitized at 1800 deg F) and to simulate Regulatory Guide 1.99 database materials (austenitized at 1600 deg. F). These heat treatments produced different microstructures so the effect of microstructure on irradiation damage sensitivity could be tested. Because the nickel content of the test plates varied and the copper level was constant, the effect of nickel on irradiation embrittlement was also tested. Correlation monitor material, HSST-02, was included in the program to benchmark the Ford Nuclear Reactor (U. of Michigan Test Reactor) which had never been used for this type of irradiation program. Materials taken from plate surface locations (vs. 1/4T) were included to test whether or not the improved toughness properties of the plate surface layer, resulting from the rapid quench, is maintained after irradiation. If the improved properties are maintained, pressurized thermal shock calculations could utilize this margin. Finally, for one experiment, irradiations were conducted at two irradiation temperatures (500 deg. F and 550 deg. F) to determine the effect of irradiation temperature on embrittlement. The preliminary results of the irradiation program show an increase in T 30 shift of 69 deg. F for a decrease in irradiation temperature of 50 deg. F. The results suggest that for nickel bearing steels, the superior toughness of plate surface material is maintained after irradiation and for the copper content tested, nickel had no apparent effect on irradiation response. No apparent microstructure

Studies of electron-beam irradiation on ethylene-styrene interpolymers

CERN Document Server

Liu, I C

2002-01-01

Electron-beam irradiation-induced structural and properties changes on ethylene-styrene interpolymers (ESI) have been studied at electron doses ranging from 0 to 200 kGy. The amounts of species generated by irradiation such as hydroxyls, hydroperoxides, carbonyls and unsaturated double bonds have been analyzed using ATR-FTIR. While the structural changes are minimal for ESI69 comprising 69 wt.% styrene regardless of the dose level, the changes for ESI40 comprising 40 wt.% styrene are dose dependent and reaches a maximum at a dose of 100 kGy. Gel permeation chromatography analysis indicates that macromolecular chain scission occurs at low irradiation dose and crosslinking dominates at high irradiation doses. The average molecular weights between crosslinks, M sub C 's, have been calculated using the Flory-Rehner equation based on data collected from solvent extraction experiments. The M sub C 's of ESI40 samples are much smaller than those of ESI69 samples. Irradiated ESI samples have higher glass transition t...

Study on quality control of Chinese herb medicine irradiation

International Nuclear Information System (INIS)

Yang Dongqing; En Lihua; Deng Wenmin

2010-01-01

6-8 kGy γ-ray irradiation dosage treatment can reduce the bacteria, mildew effectively from 105 CFU/g to 102 CFU/g and eliminate the parasite in 4 kind of Chinese herb medicine, enhance their quality of sanitation observably. In the other hand, irradiation doesn't influence the medicinal component and therapy effect. Storage study has improved that the 4 kind of Chinese herb medicine treated by γ-ray irradiation can be preserved over one year in the room temperature with high quality of sanitation and steady medicinal component. (authors)

Study on the sterilization of egg white powder by irradiation

International Nuclear Information System (INIS)

Fu Lixin; Meng Lifen; Zhao Xiaonan; Xu Dechun; Hu Shaoxin; Chen Changdong; Pei Ying

2012-01-01

The article studied the killing microorganism result, the influence of main essential nutrient and sense organ of egg white powder by Co-60 γ-ray irradiation. The microorganism index of the egg white powder samples can meet the government food sanitation standard by 4 kGy irradiation, and the killing microorganism rare can reach 100%. The irradiation dose from 4 to 10 kGy has little influence to the egg white powder protein, crude fiber and amino acids contras ting to comparison, and the sensory quality such as color and luster, scent has little change below 6 kGy irradiation. Synthesizing the results of physical chemistry and sense organ, the optimal irradiation dose of egg white powder killing microorganism is 4 to 6 kGy. (authors)

Study on the sterilization of egg white powder by irradiation

International Nuclear Information System (INIS)

Fu Lixin; Meng Lifen; Zhao Xiaonan; Xu Dechun; Hu Shaoxin; Chen Changdong; Pei Ying

2011-01-01

The article studied the killing microorganism result, the influence of main essential nutrient and sense organ of egg white powder by Co-60 γ-ray irradiation. The microorganism index of the egg white powder samples can meet the government food 1 sanitation standard by 4 kGy irradiation, and the killing microorganism rare can reach 100%. The irradiation dose from 4 to 10 kGy has little influence to the egg white powder protein, crude fiber and amino acids contrasting to comparison, and the sensory quality such as color and luster, scent has little change below 6 kGy irradiation. Compositing the result of physical chemistry and sense organ, the optimal irradiation dose of egg white powder killing microorganism is 4 to 6 kGy. (authors)

Conductivity in insulators due to implantation of conducting species

International Nuclear Information System (INIS)

Prawer, S.; Kalish, R.

1993-01-01

Control of the surface conductivity of insulators can be accomplished by high dose ion implantation of conductive species. The use of C + as the implant species is particularly interesting because C can either form electrically insulating sp 3 bonds or electrically conducting sp 2 bonds. In the present work, fused quartz plates have been irradiated with 100 keV C + ions to doses up to 1 x 10 17 ions/cm 2 at room temperature and at 200 deg C. The ion beam induced conductivity was monitored in-situ and was found to increase by up to 8 orders to magnitude for the ion dose range studied. Xe implantations over a similar range did not induce any changes in the conductivity showing that the increase in conductivity is caused by the presence of the C in the fused quartz matrix and not by damage. The dependence of the conductivity on implantation temperature and on post implantation annealing sheds light on the clustering of the C implants. The temperature dependence of the conductivity for the highest doses employed (1 x 10 17 C + /cm 2 ) can be described very well by lnσ α T. This is considered to be a peculiar dependence which does not comply with any of the standard models for conduction. 9 refs., 1 tab., 6 figs

Moessbauer study of defects in molybdenum and chromium irradiated with ions

International Nuclear Information System (INIS)

Troyan, V.A.; Bogdanov, V.V.; Ivanyushkin, E.M.; Pen'kov, Yu.P.

1980-01-01

Effects of ion irradiation of monocrystalline molybdenum and polycrystalline chromium with Co-57 impurity were studied by Moessbauer effect. Molybdenum specimens were irradiated by He + ions at accelerators with 40 keV energy. Chromium specimens were irradiated by hydrogen ions with 1.2 MeV energy up to integral 2x10 17 -2x10 19 ion/cm 2 doses. It is shown, that defect introduction into the source matrix by irradiation results in change of gamma-resonance line form and effect value. The observed effects of defect influence on spectrum parameters are discussed. It is concluded, that study of Moessbauer spectra parameters of diluted Co-57 solutions in matrices of different metals permits to determine dynamics of movement of impurity atoms and defects in metals irradiated with ions [ru

The effect of composition, electron irradiation and quenching on ...

Indian Academy of Sciences (India)

The ionic conductivity at room temperature exhibits a characteristic double peak for the composition = 20 and 70. Both electron beam irradiation and quenching at low temperature have resulted in an increase in conductivity by 1–2 orders of magnitude. The enhancement of conductivity upon irradiation and quenching is ...

Electron microscope study of irradiated beryllium oxide; Etude au microscope electronique de l'oxyde de beryllium irradie

Energy Technology Data Exchange (ETDEWEB)

Bisson, A A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-06-01

The beryllium oxide is studied first by fractography, before and after irradiation, using sintered samples. The fractures are examined under different aspects. The higher density sintered samples, with transgranular fractures are the most interesting for a microscopic study. It is possible to mark the difference between the 'pores' left by the sintering process and the 'bubbles' of gases that can be produced by former thermal treatments. After irradiation, the grain boundaries are very much weakened. By annealing, it is possible to observe the evolution of the gases produced by the reaction (n, 2n) and (n. {alpha}) and gathered on the grain boundaries. The irradiated beryllium oxide is afterwards studied by transmission. For that, a simple method has been used: little chips of the crushed material are examined. Clusters of point defects produced by neutrons are thus detected in crystals irradiated at the three following doses: 6 x 10{sup 19}, 9 x 10{sup 19} and 2 x 10{sup 20} n{sub f} cm{sup -2} at a temperature below 100 deg. C. For the irradiation at 6 x 10{sup 19} n{sub f} cm{sup -2}, the defects are merely visible, but at 2 x l0{sup 20} n{sub f} cm{sup -2} the crystals an crowded with clusters and the Kikuchi lines have disappeared from the micro-diffraction diagrams. The evolution of the clusters into dislocation loops is studied by a series of annealings. The activation energy (0,37 eV) calculated from the annealing curves suggests that it must be interstitials that condense into dislocation loops. Samples irradiated at high temperatures (650, 900 and 1100 deg. C) are also studied. In those specimens the size of the loops is not the same as the equilibrium size obtained after out of pile annealing at the same temperature. Those former loops are more specifically studied and their Burgers vector is determined by micro-diffraction. (author) [French] L'oxyde de beryllium est d'abord etudie, par une methode fractographique, avant et apres irradiation, en

Food irradiation for phytosanitary and quarantine treatment

Science.gov (United States)

Irradiation at doses less than 1 kGy is an effective phytosanitary measure with minimal adverse effects on the quality of most fresh produce. There are internationally recognized guidelines for the use of irradiation as a phytosanitary measure and for the conduct of trade in irradiated fresh produce...

Economic feasibility study of potato preservation by irradiation in saudi arabia

Energy Technology Data Exchange (ETDEWEB)

Kinsara, A A; Abulfaraj, W H; Mamoon, A M; Kamal, S E [Nuclear Engineering Department, Faculty of Engineering, King Abdulaziz University, Jeddah (Saudi Arabia)

1997-12-31

Comprehensive studies were carried out to investigate the economic feasibility of the preservation of potato crop by cobalt-60 gamma irradiation sprout inhibition by potato irradiation was approved by international organization and concerned authorities in many countries. The dose level range authorized for potato sprout inhibition extends from about 80-150 Gy depending on potato variety, time of irradiation after harvest, and post irradiation storage temperature. Sprout inhibition is most effective by irradiation after harvest, and after healing of any inflicted injuries, that when the potatoes are dormant. Irradiation at the recommended doses minimizes storage losses of potatoes that are refrigerated or stored on shelves. Despite the limited data available, an attempt was made to quantify the monetary value of preserving potato by irradiation. With economy scale taken in consideration, potato preservation by irradiation is economically feasible since at the local consumption rates there will be lot of potatoes that ned storage for off season use. 5 tabs.

Study on the storage properties of irradiated ginger

International Nuclear Information System (INIS)

Wang Shoujing; Yu Zihou; Sun Shouyi; Zou Jiwan; Zhang Qizhi; Sun Hongchun; Lv Tiexin; Liu Xiaoyong

2004-01-01

The γ-ray irradiation could cause the loss of Vc during the early stage of storage, however, after 150 days' storage there were no significant differences of Vc content between irradiated and non-irradiated samples. The content of reduced sugar was increased by irradiation especially with 150 and 250 Gy. When ginger were irradiated with 250 Gy and stored at room temperature for 120 days, the content of Met and Arg decreased obviously, but the contents of other 16 amino acids were not affected. The respiration rate of irradiated ginger reached its peak at 7-9 days of storage, and from then it kept lower level for the rest storage time. The electrolyte permeability increased slightly after γ-irradiation. Irradiation with 80-400 Gy had no effects on lipid isoenzyme zymogram

Study of the stability of the tragacanto rubber irradiated

International Nuclear Information System (INIS)

Rodriguez, M.; Romero, M.; Montes de Oca, N.

2001-01-01

Presently work was studied the processing by radiations of the tragacanto rubber powdered, with ends of achieving its sterilization. For the irradiation, the envelopes were placed in aluminum containers to reason of an envelope for container. The material underwent analysis of its viscosity and microbiological tests. They got ready solutions, according to the British pharmacopoeia, starting from the material irradiated with dose of D0-0, D1-5, D2-7.5, and D3-10 kGy. The smaller than the applied doses (5kGy) it produced a variation of 72% in the viscosity of the solutions, in comparison with the rubber without irradiating. They were carried out tests of sterility to the material irradiated with inferior dose of 5 kGy, being contaminated in all the cases

Studies On Quality Criteria For Irradiated Breaded Chicken Breast Fillets

International Nuclear Information System (INIS)

HASSAN, I.M.; IBRAHIM, M.T.; MAHMOUD, A.A.; SHAMS EL DIN, N.M.M.; MOHAMMAD, M.K.

2010-01-01

Quality criteria of irradiated breaded chicken breast fillets were studied. Fresh boneless and skinless breaded chicken breast meats samples were divided into four separate batches and packed in plastic bags and sealed by an impulse sealer. Samples in plastic bags were exposed to different doses of gamma irradiation (2.5, 5 and 7 kGy) at ambient temperature. Just after irradiation, the samples were stored at 4 ±1 0 C. All samples were evaluated for microbiological, chemical and sensorial properties after irradiation and throughout the storage periods. During storage, the total bacterial count was significantly increased (P<0.05) in all samples with higher rates of increase in non-irradiated samples. In all irradiated samples, Staphylococcus aureus did not detected up to 6 days then detected after 22 days in samples treated with 2.5 kGy as well as 31 days in samples treated with 5 kGy. On the other hand, Staphylococcus aureus was detected after 45 days in samples treated with 7 kGy. Salmonella sp., Listeria monocytogenes and Campylobacter jejuni could not detected in untreated and treated samples. The protein content showed significant decrease immediately after irradiation and during the refrigerated storage. The TVN values for non-irradiated samples were significantly higher (P<0.05) than irradiated samples. The present data showed significant decrease (P<0.05) in protein solubility percentages of irradiated samples at day 0 and 6 of refrigerated storage. The observed decrease was related to the increase of radiation dose. At the end of storage period (62 days), 2.5 kGy samples were significantly higher in TBA values than other irradiated samples. On the other hand, irradiation was significantly reduced (P<0.05) the amount of major mono unsaturated and poly unsaturated fatty acids. Sensory attributes of breaded chicken breast fillets did not affected by irradiation. It could be concluded that irradiation dose of 5 kGy can be used in chicken samples stored in

Positron annihilation studies on reactor irradiated and thermal annealed ferrocene

International Nuclear Information System (INIS)

Marques Netto, A.; Carvalho, R.S.; Magalhaes, W.F.; Sinisterra, R.D.

1996-01-01

Retention and thermal annealing following (n, γ) reaction in solid ferrocene, Fe(C 5 H 5 ) 2 , were studied by positron annihilation lifetime spectroscopy (PAL). Positronium (Ps) formation was observed in the non-irradiated compound with a probability or intensity (I 3 ) of 30%. Upon irradiation of the compound with thermal neutrons in a nuclear reactor, I 3 decreases with increasing irradiation time. Thermal treatment again increases I 3 values from 16% to 25%, revealing an important proportion of molecular reformation without variation of the ortho-positronium lifetime (τ 3 ). These results point out the major influence of the electronic structure as determining the Ps yields in the pure complex. In the irradiated and non irradiated complexes the results are satisfactorily explained on the basis of the spur model. (orig.)

Thermal Decompositon Studies Of Pre-Irradiated Nickel (II) Azides ...

African Journals Online (AJOL)

The effect of pre-irradiation on the thermal decomposition of three samples of nickel (II) azide was studied. It was found that the rates of thermal decomposition of Ni(OH)N3 increased substantially with increase in pre-irradiation dosage. The initial reaction rates change from time-dependant nucleation law for the unirradiated ...

Experimental and theoretical study of solid solution stability under irradiation

International Nuclear Information System (INIS)

Cauvin, Richard.

1981-08-01

The behavior of dilute alloys (Al-Zn, Al-Ag, Al-Si, Al-Ge and Al-Mg) under 1 MeV electron irradiation has been studied in a high voltage electron microscope. A phenomenon of homogeneous precipitation induced by irradiation in undersaturated solid solutions (Al-Zn, Al-Ag and Al-Si) has been discovered; the observed precipitates are either coherent or incoherent, but never associated with point defect sinks. The solubility limit is a function of irradiation temperature and flux; but, under irradiation, it does not behave as a true thermal solubility limit (without irradiation). The existing theories (kinetic or strictly thermodynamic) do not account for this phenomenon. It is shown that the irreversibility of the mutual recombination between trapped vacancies and mixed interstitials is the driving force of this homogeneous precipitation. Using a dilute solid solution model, we show that, under irradiation, the homogeneous stationary state, stable from a strictly thermodynamic point of view, can be unstable when the recombination reaction is taken into account. The solubility limit under irradiation is calculated with a nucleation-growth model taking account for this effect; it is proportional to the thermal solubility limit without irradiation. This model explains all the experimental observations [fr

Damage studies on tungsten due to helium ion irradiation

International Nuclear Information System (INIS)

Dutta, N.J.; Buzarbaruah, N.; Mohanty, S.R.

2014-01-01

Highlights: • Used plasma focus helium ion source to study radiation induced damage on tungsten. • Surface analyses confirm formation of micro-crack, bubbles, blisters, pinholes, etc. • XRD patterns confirm development of compressive stress due to thermal load. • Reduction in hardness value is observed in the case of exposed sample. - Abstract: Energetic and high fluence helium ions emitted in a plasma focus device have been used successfully to study the radiation induced damage on tungsten. The reference and irradiated samples were characterized by optical microscopy, field emission scanning electron microscopy, X-ray diffraction and by hardness testers. The micrographs of the irradiated samples at lower magnification show uniform mesh of cracks of micrometer width. However at higher magnification, various types of crystalline defects such as voids, pinholes, bubbles, blisters and microcracks are distinctly noticed. The prominent peaks in X-ray diffraction spectrum of irradiated samples are seen shifted toward higher Bragg angles, thus indicating accumulation of compressive stress due to the heat load delivered by helium ions. A marginal reduction in hardness of the irradiated sample is also noticed

EPR study on non- and gamma-irradiated herbal pills

Energy Technology Data Exchange (ETDEWEB)

Aleksieva, K., E-mail: katerina_bas@abv.b [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Lagunov, O. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Dimov, K. [Institute of Cryobiology and Food Technologies, 1162 Sofia (Bulgaria); Yordanov, N.D. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

2011-06-15

The results of EPR studies on herbal pills of marigold, hawthorn, yarrow, common balm, tutsan, nettle and thyme before and after gamma-irradiation are reported. Before irradiation all samples exhibit one weak singlet EPR line with a g-factor of 2.0048{+-}0.0005. After irradiation herbal pills could be separated in two groups according to their EPR spectra. Radiation-induced free radicals in pills of marigold, yarrow, nettle, tutsan and thyme could be attributed mainly to saccharide excipients. Tablets of hawthorn and common balm show 'cellulose-like' EPR spectrum, superimposed on partly resolved carbohydrate spectrum, due to the active part (herb) and inulin, which is present in the pills as an excipient. Fading study of the radiation-induced EPR signals confirms that sugar radicals are more stable than cellulose species. The reported results show that the presence of characteristic EPR spectra of herbal pills due to excipients or active part can be used as unambiguous proof of radiation processing within 35 or more days after irradiation.

Experimental study on active specific immunotherapy modified with irradiation

International Nuclear Information System (INIS)

Imanaka, Kazufumi; Ogawa, Yasuhiro; Gose, Kyuhei; Imajo, Yoshinari; Kumura, Shuji

1982-01-01

We have already reported that the effectiveness of active specific immunotherapy using irradiated tumor cells and infiltrating mononuclear cells which were separated from the topical tumor tissue 7 days after irradiation of 2,000 rad in experimental study. The present study was designed to investigate the effect of non-specific immunopotentiator PS-K combined with active specific immunotherapy. Female C3H/He mice aged 12 weeks were inoculated 4 x 10 6 MM 46 tumor cells in the right hind paws and received local electron irradiation with the dose of 3,000 rad on the 5th day after irradiation. Active specific immunotherapy was performed on the 12th day, and daily dose of 200 mg/kg of PS-K was injected intraperitoneally from the 6th day to the 10th day. The inhibition of the tumor growth and the elongation of survival period were noted in the group which received active specific immunotherapy combined with non-specific immunopotentiator, PS-K compared with the active specific immunotherapy alone. (author)

EPR study on non- and gamma-irradiated herbal pills

International Nuclear Information System (INIS)

Aleksieva, K.; Lagunov, O.; Dimov, K.; Yordanov, N.D.

2011-01-01

The results of EPR studies on herbal pills of marigold, hawthorn, yarrow, common balm, tutsan, nettle and thyme before and after gamma-irradiation are reported. Before irradiation all samples exhibit one weak singlet EPR line with a g-factor of 2.0048±0.0005. After irradiation herbal pills could be separated in two groups according to their EPR spectra. Radiation-induced free radicals in pills of marigold, yarrow, nettle, tutsan and thyme could be attributed mainly to saccharide excipients. Tablets of hawthorn and common balm show 'cellulose-like' EPR spectrum, superimposed on partly resolved carbohydrate spectrum, due to the active part (herb) and inulin, which is present in the pills as an excipient. Fading study of the radiation-induced EPR signals confirms that sugar radicals are more stable than cellulose species. The reported results show that the presence of characteristic EPR spectra of herbal pills due to excipients or active part can be used as unambiguous proof of radiation processing within 35 or more days after irradiation.

EPR study on non- and gamma-irradiated herbal pills

Science.gov (United States)

Aleksieva, K.; Lagunov, O.; Dimov, K.; Yordanov, N. D.

2011-06-01

The results of EPR studies on herbal pills of marigold, hawthorn, yarrow, common balm, tutsan, nettle and thyme before and after gamma-irradiation are reported. Before irradiation all samples exhibit one weak singlet EPR line with a g-factor of 2.0048±0.0005. After irradiation herbal pills could be separated in two groups according to their EPR spectra. Radiation-induced free radicals in pills of marigold, yarrow, nettle, tutsan and thyme could be attributed mainly to saccharide excipients. Tablets of hawthorn and common balm show "cellulose-like" EPR spectrum, superimposed on partly resolved carbohydrate spectrum, due to the active part (herb) and inulin, which is present in the pills as an excipient. Fading study of the radiation-induced EPR signals confirms that sugar radicals are more stable than cellulose species. The reported results show that the presence of characteristic EPR spectra of herbal pills due to excipients or active part can be used as unambiguous proof of radiation processing within 35 or more days after irradiation.

Studies in mice fed a diet containing irradiated fish

International Nuclear Information System (INIS)

1979-01-01

Three groups of mice were observed in utero and for eighty (80) weeks thereafter to study growth, food consumption, hematology, blood chemistry and survival with particular interest in carcinogenic potential. Group I received only Purina Mouse Chow, Group II received a diet composed of 45% non-irradiated fish and 55% Purina Mouse Chow, and Group III received a diet composed of 45% gamma irradiated fish and 55% Purina Mouse Chow. Differences observed in body weights between control and fish treated diets were due to the incorporation of fish into the diet and not the results of fish being treated with gamma irradiation. Differences observed in food consumption between control and fish treated diets were due to the incorporation of fish into the diet and not the result of fish being treated with gamma irradiation. No daily observations were made which could be attributed to the treatment of fish with gamma irradiation. No observations were made at any time interval for hematology which could be attributed to the treatment of fish with gamma irradiation. No observations were made at any time interval for clinical chemistry which could be attributed to the treatment of fish with gamma irradiation. Palpable mass data did not reveal any trends which could be related to the treatment of fish with gamma irradiation. Gross observations at necropsy were limited to spontaneously occurring lesions or artifacts of necropsy technique commonly associated with animals of this species and age. Organ weight data did not reveal any trends which could be related to the treatment of fish with gamma irradiation. Pathological findings were limited to spontaneously occurring lesions or artifacts of necropsy technique commonly associated with animals of this species and age. (orig.)

Photoluminescence and reflectivity studies of high energy light ions irradiated polymethyl methacrylate films

Science.gov (United States)

Bharti, Madhu Lata; Singh, Fouran; Ramola, R. C.; Joshi, Veena

2017-11-01

The self-standing films of non-conducting polymethyl methacrylate (PMMA) were irradiated in vacuum using high energy light ions (HELIs) of 50 MeV Lithium (Li+3) and 80 MeV Carbon (C+5) at various ion dose to induce the optical changes in the films. Upon HELI irradiation, films exhibit a significant enhancement in optical reflectivity at the highest dose. Interestingly, the photoluminescence (PL) emission band with green light at (514.5 nm) shows a noticeable increase in the intensity with increasing ion dose for both ions. However, the rate of increase in PL intensity is different for both HELI and can be correlated with the linear energy transfer by these ions in the films. Origin of PL is attributed to the formation of carbon cluster and hydrogenated amorphous carbon in the polymer films. HAC clusters act as PL active centres with optical reflectivity. Most of the harmful radiation like UV are absorbed by the material and is becoming opaque after irradiation and this PL active material are useful in fabrication of optoelectronic devices, UV-filter, back-lit components in liquid crystal display systems, micro-components for integrate optical circuits, diffractive elements, advanced materials and are also applicable to the post irradiation laser treatment by means of ion irradiation.

Study on neutron irradiation behavior of beryllium as neutron multiplier

Energy Technology Data Exchange (ETDEWEB)

Ishitsuka, Etsuo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

1998-03-01

More than 300 tons beryllium is expected to be used as a neutron multiplier in ITER, and study on the neutron irradiation behavior of beryllium as the neutron multiplier with Japan Materials Testing Reactor (JMTR) were performed to get the engineering data for fusion blanket design. This study started as the study on the tritium behavior in beryllium neutron reflector in order to make clear the generation mechanism on tritium of JMTR primary coolant since 1985. These experiences were handed over to beryllium studies for fusion study, and overall studies such as production technology of beryllium pebbles, irradiation behavior evaluation and reprocessing technology have been started since 1990. In this presentation, study on the neutron irradiation behavior of beryllium as the neutron multiplier with JMTR was reviewed from the point of tritium release, thermal properties, mechanical properties and reprocessing technology. (author)

Latin American regional co-operative programme on food irradiation

International Nuclear Information System (INIS)

1992-06-01

The ''Latin American Regional Co-ordinated Research Programme on Food Irradiation'' was established in 1986 with the participation of research scientists from countries in the region to investigate the efficacy of food irradiation as a treatment to reduce post-harvest losses and improve the hygienic quality of food, to conduct techno-economic feasibility studies, and to disseminate knowledge about the scientific, health, legal and commercial aspects of food irradiation. This publication contains the final report of the Co-ordinated Research Programme and summaries of individual research reports presented by the participating scientists

Kinetics of phenol degradation in water solutions under gamma-irradiation

International Nuclear Information System (INIS)

Guliyeva, U.A.; Gurbanov, M.A.; Abdullayev, E.T.

2014-01-01

Full text : In this work the chemical oxygen demand and change of phenol concentration at the radiolysis of aqueous solutions of phenol was studied. Irradiation conducted under gamma-irradiation of 60Co at static conditions and at room temperature. The main component is water, therefore the radiolysis process of water plays an important role in radiolytic degradation of phenol

Fundamental Studies of Irradiation-Induced Modifications in Microstructural Evolution and Mechanical Properties of Advanced Alloys

Energy Technology Data Exchange (ETDEWEB)

Stubbins, James; Heuser, Brent; Hosemann, Peter; Liu, Xiang

2018-04-24

This final technical report summarizes the research performed during October 2014 and December 2017, with a focus on investigating the radiation-induced microstructural and mechanical property modifications in optimized advanced alloys for sodium-cooled fast reactor (SFR) structural applications. To accomplish these objectives, the radiation responses of several different advanced alloys, including austenitic steel Alloy 709 (A709) and 316H, and ferritic/ martensitic Fe–9Cr steels T91 and G92, were investigated using a combination of microstructure characterizations and nanoindentation measurements. Different types of irradiation, including ex situ bulk ion irradiation and in situ transmission electron microscopy (TEM) ion irradiation, were employed in this study. Radiation-induced dislocations, precipitates, and voids were characterized by TEM. Scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM-EDS) and/or atom probe tomography (APT) were used to study radiation-induced segregation and precipitation. Nanoindentation was used for hardness measurements to study irradiation hardening. Austenitic A709 and 316H was bulk-irradiated by 3.5 MeV Fe++ ions to up to 150 peak dpa at 400, 500, and 600°. Compared to neutron-irradiated stainless steel (SS) 316, the Frank loop density of ion-irradiated A709 shows similar dose dependence at 400°, but very different temperature dependence. Due to the noticeable difference in the initial microstructure of A709 and 316H, no systematic comparison on the Frank loops in A709 vs 316H was made. It would be helpful that future ion irradiation study on 316 stainless steel could be conducted to directly compare the temperature dependence of Frank loop density in ion-irradiated 316 SS with that in neutron-irradiated 316 SS. In addition, future neutron irradiation on A709 at 400–600° at relative high dose (>10 dpa) can be carried out to compare with ion-irradiated A709. The radiation

Irradiation-induced permeability in pyrocarbon coatings. Final report of work conducted under PWS FD-12

International Nuclear Information System (INIS)

Kania, M.J.; Thiele, B.A.; Homan, F.J.

1982-10-01

Two US irradiation experiments were planned to provide information to supplement data from the German program on irradiation-induced permeability in pyrocarbon coatings. Hopefully, the data from both programs could be combined to define the onset of neutron-induced permeability in a variety of Biso coatings produced with different process variables (coating temperature, coating gases, and coating rates). The effort was not successful. None of the preirradiation characterization procedures were able to adequately predict irradiation performance. A large amount of within-batch scatter was observed in the fission gas and cesium release data along with significant within-batch variation in coating properties. Additional preirradiation characterization might result in a procedure that could successfully predict irradiation performance, but little can be done about the within-batch variation in coating properties. This variation is probably the result of random movement of particles within the coating furnace during pyrocarbon deposition. 19 figures, 4 tables

Re-crystallization of ITO films after carbon irradiation

Energy Technology Data Exchange (ETDEWEB)

Usman, Muhammad, E-mail: usmanm@ncp.edu.pk [Experimental Physics Laboratories, National Centre for Physics, Shahdara Valley Road, Quaid-i-Azam University, Islamabad (Pakistan); Khan, Shahid, E-mail: shahidkhan@zju.edu.cn [State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Khan, Majid [Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan); Abbas, Turab Ali [Experimental Physics Laboratories, National Centre for Physics, Shahdara Valley Road, Quaid-i-Azam University, Islamabad (Pakistan)

2017-01-15

Highlights: • Carbon irradiation on ITO destroys crystal structure until threshold ion fluence. • Carbon irradiation induced amorphization in ITO is recoverable at higher fluence. • Optical transmittance is reduced after carbon irradiation. • Electrical resistivity is increased after irradiation with carbon ions in ITO. • Bandgap is reduced with increasing fluence of carbon irradiation. - Abstract: 2.0 MeV carbon ion irradiation effects on Indium Tin Oxide (ITO) thin films on glass substrate are investigated. The films are irradiated with carbon ions in the fluence range of 1 × 10{sup 13} to 1 × 10{sup 15} ions/cm{sup 2}. The irradiation induced effects in ITO are compared before and after ion bombardment by systematic study of structural, optical and electrical properties of the films. The XRD results show polycrystalline nature of un-irradiated ITO films which turns to amorphous state after 1 × 10{sup 13} ions/cm{sup 2} fluence of carbon ions. Further increase in ion fluence to 1 × 10{sup 14} ions/cm{sup 2} re-crystallizes the structure and retains for even higher fluences. A gradual decrease in the electrical conductivity and transmittance of irradiated samples is observed with increasing ion fluence. The band gap of the films is observed to be decreased after carbon irradiation.

Re-crystallization of ITO films after carbon irradiation

International Nuclear Information System (INIS)

Usman, Muhammad; Khan, Shahid; Khan, Majid; Abbas, Turab Ali

2017-01-01

Highlights: • Carbon irradiation on ITO destroys crystal structure until threshold ion fluence. • Carbon irradiation induced amorphization in ITO is recoverable at higher fluence. • Optical transmittance is reduced after carbon irradiation. • Electrical resistivity is increased after irradiation with carbon ions in ITO. • Bandgap is reduced with increasing fluence of carbon irradiation. - Abstract: 2.0 MeV carbon ion irradiation effects on Indium Tin Oxide (ITO) thin films on glass substrate are investigated. The films are irradiated with carbon ions in the fluence range of 1 × 10"1"3 to 1 × 10"1"5 ions/cm"2. The irradiation induced effects in ITO are compared before and after ion bombardment by systematic study of structural, optical and electrical properties of the films. The XRD results show polycrystalline nature of un-irradiated ITO films which turns to amorphous state after 1 × 10"1"3 ions/cm"2 fluence of carbon ions. Further increase in ion fluence to 1 × 10"1"4 ions/cm"2 re-crystallizes the structure and retains for even higher fluences. A gradual decrease in the electrical conductivity and transmittance of irradiated samples is observed with increasing ion fluence. The band gap of the films is observed to be decreased after carbon irradiation.

The preliminary study on peculiar flavor from irradiated dried duck

International Nuclear Information System (INIS)

Li Zongju; Chen Zongdao; Xu Denyi

1992-01-01

Peculiar flavor may be induced from irradiative preservation of meat with higher dose. The study on the irradiation of dried duck indicated that peculiar flavor is produced by a threshold of 1.5 kGy and intensifies with the increase of dose. The flavor primarily comes from muscle of dried duck especially from its water soluble protein. With the increase of dose, volatile carbonyl compounds, amines and sulfur compounds increased significantly. Paper chromatography analysis shows that two new volatile carbonyl compounds (R f =0.23 and 0.28) and a new volatile amine-propamine are induced by irradiation. This compounds may be the source of peculiar flavor in irradiated dried duck

Irradiation-related amorphization and crystallization: In situ transmission electron microscope studies

International Nuclear Information System (INIS)

Allen, C.W.

1994-01-01

Interfacing an ion accelerator to a transmission electron microscope (TEM) allows the analytical functions of TEM imaging and diffraction to be employed during ion-irradiation effects studies. At present there are twelve such installations in Japan, one in France and one in the US. This paper treats several aspects of in situ studies involving electron and ion beam induced and enhanced phase transformations and presents results of several in situ experiments to illustrate the dynamics of this approach in the materials science of irradiation effects. The paper describes the ion- and electron-induced amorphization of CuTi; the ion-irradiation-enhanced transformation of TiCr 2 ; and the ion- and electron-irradiation-enhanced crystallization of CoSi 2

Preliminary study on detection of irradiated foodstuffs from the Romanian market

International Nuclear Information System (INIS)

Cutrubinis, Mihalis; Chirita, Daniel; Savu, Diana; Elisabeta Secu, Corina; Mihai, Radu; Secu, Mihai; Ponta, Corneliu

2007-01-01

In order to fulfil the European task for market survey in food irradiation the first Romanian laboratory for detection of irradiated foodstuffs was established at IRASM Irradiation Centre. In this preliminary study, a wide range of Romanian food samples (spices, vegetables and meat) gamma irradiated at IRASM have been studied using different detection methods: (1) DNA comet assay, (2) thermoluminescence (TL) and (3) electron spin resonance (ESR) for foodstuffs containing bone or cellulose. The results suggest that there is no general available detection method and there is no perfect detection method. In conclusion, in order to carry out a correct identification of radiation treatment of a food sample it is recommended to use at least two standardised detection methods

Positron lifetime study of copper irradiated by energetic protons or energetic neutrons

International Nuclear Information System (INIS)

Howell, R.H.

1979-03-01

Positron lifetime measurements of pure copper damaged by irradiation with energetic protons and neutrons are presented. Lifetime determinations of the bulk material and various traps were made, and the dependence of the trapping rate on dose and irradiation energy were investigated. The results from the neutron- and proton-irradiated samples point to the existence of traps with similar but distinct lifetime parameters, not varying greatly from values reported in deformation studies. Also, a trap with long lifetime is seen for some proton irradiations, but is never seen for the neutron irradiations. The trapping rate of the short-lifetime trap is a linear function of dose for proton-irradiated samples and nearly so for the neutron irradiation. 1 figure

Disorder and conductivity of organic metal

International Nuclear Information System (INIS)

Bouffard, Serge

1982-02-01

At high temperature, quasi-one-dimensional organic conductors are metallic; at low temperature, the electron gas instabilities drive either a metal to insulator transition or a metal to superconductor transition. Precursors of these 3-D ordering could be appear at higher temperature. A study of the effects of irradiation induced defects on a few organic complexes has shown that defects are produced by radiolitic process. Their concentration can be easily deduced from resistivity measurement at room temperature. In the metallic state, the defects act as strong potentials which break the conducting chains and force the electron to jump to the neighbourg stack. The defects produce a mixing between longitudinal and transverse conductivities. While, it is the 3-D effect of the defects which pins the charge density waves and thus the 3-D ordering can not be acheived: the metal to insulator transition is destroyed, the metallic state is stabilized. In the same time, the fluctuative conductivity is suppress. The superconducting regime has been found to be extremely sensitive to irradiation induced defects. Thus we can demonstrate that the 1-D superconducting fluctuations contribute to the conductivity and that the transition temperature is correlated to the 3-D superconducting fluctuations. [fr

Vacancy defects in electron irradiated RPV steels studied by positron lifetime

Energy Technology Data Exchange (ETDEWEB)

Moser, P; Li, X H [CEA Centre d` Etudes de Grenoble, 38 (France). Dept. de Recherche Fondamentale sur la Matiere Condensee; Akamatsu, M; Van Duysen, J C [Electricite de France (EDF), 77 - Ecuelles (France)

1994-12-31

Specimens of French RPV (reactor pressure vessels) steels at different rates of segregation have been irradiated at 150 and 288 deg C with 3 MeV electrons (irradiation dose: 4*10{sup 19} e-/cm{sup 2}). Vacancy defects are studied by positron lifetime measurements before and after irradiation and at each step of isochronal annealing. After 150 deg C irradiation, a recovery step is observed in both specimens, for annealing treatments in the range 220-370 deg C and is attributed to the dissociation of vacancy-impurity complexes. The size of vacancy clusters never overcome 10 empty atomic volumes. If ``fresh`` dislocations are created just before irradiation, big vacancy clusters could be formed. After 288 deg C irradiation, small vacancy cluster of 4-10 empty atomic volumes are observed. (authors). 3 figs., 7 refs.

Thermoluminescence and chemiluminescence measurement as routine screening method for identification of irradiated spices. Studies to establish limiting values for differentiation of irradiated and non-irradiated samples. Thermolumineszenz- und Chemilumineszenzmessungen als Routine-Methoden zur Identifizierung strahlenbehandelter Gewuerze. Untersuchungen zur Festlegung von Grenzwerten fuer die Unterscheidung bestrahlter von unbestrahlten Proben

Energy Technology Data Exchange (ETDEWEB)

Heide, L; Albrich, S; Mentele, E; Boegl, W

1987-04-01

The reported experiments with non-irradiated and ..gamma..-irradiated spices of different origin were conducted to determine the variation in chemiluminescence and thermoluminescence intensity for each individual spice. 29 spices from 7 to 10 different manufacturers have been examined, taking into account the influence of storage time. In order to evaluate the methods, the results are represented in diagrams and tables enabling light emission limits to be given for differentiation between irradiated and non-irradiated samples. The final section of this report contains a conclusive evaluation of the present state of chemiluminescence and thermoluminescence analysis for the detection of irradiated spices.

Self-irradiation effect on thermal conductivity of Zr{sub 0.70}Pu{sub 0.25}Cm{sub 0.05}N solid solution

Energy Technology Data Exchange (ETDEWEB)

Nishi, Tsuyoshi, E-mail: tsuyoshi.nishi.75@vc.ibaraki.ac.jp [Department of Materials Science and Engineering, College of Engineering, Ibaraki University, Hitachi, Ibaraki, 316-8511 (Japan); Hayashi, Hirokazu; Sato, Takumi; Takano, Masahide [Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai-mura, Ibaraki, 319-1195 (Japan)

2017-04-01

This study evaluated the dependence of the thermal conductivity of Zr{sub 0.70}Pu{sub 0.25}Cm{sub 0.05}N on storage time and temperature. The authors prepared sintered samples of Zr{sub 0.70}Pu{sub 0.25}Cm{sub 0.05}N solid solution and measured thermal diffusivity at storage times of 0, 24, 72, 144, 240, 408, 552, 816, 1,680, and 2064 h, from which it was determined that the thermal conductivity decreased exponentially with increasing storage time. This result suggests that the decrease of the thermal conductivity could be attributed to the accumulation of lattice defects from self-irradiation. To confirm the thermal recovery behavior of Zr{sub 0.70}Pu{sub 0.25}Cm{sub 0.05}N under annealing, thermal diffusivity was also measured just after annealing. The thermal conductivity of Zr{sub 0.70}Pu{sub 0.25}Cm{sub 0.05}N was determined to be larger than that of Zr{sub 0.58}Pu{sub 0.21}Cm{sub 0.21}N but smaller than that of Zr{sub 0.80}Pu{sub 0.10}Cm{sub 0.10}N. - Highlights: •The authors prepared Zr{sub 0.70}Pu{sub 0.25}Cm{sub 0.05}N and measured thermal diffusivity. •Dependence of thermal conductivity on storage time was clarified. •After annealing at 1423 K in vacuum, thermal conductivity was recovered.

Study On Irradiated Vietnam Java Rambutan Fruit Which Was Postharvested Treatment To Prolong The Shelflife For Export Purposes

International Nuclear Information System (INIS)

Nguyen Thuy Khanh; Nguyen Thi Ly; Doan Thi The; Cao Van Chung; Nguyen Van Phong

2014-01-01

The research - Study on irradiated Vietnam Java rambutan fruit which was postharvested treatment to prolong the shelflife for export purposes - was conducted at Research and Development Center for Radiation Technology and Southern Horticultural Research Institute for 12 months. On the one hand, the theme was to study the effects of low-dose radiation in the range (200-500 Gy) combined with two types of packaging: carton boxes and carton boxes + PE perforated cover 0.5% of the area bags. After 13 days monitoring in 13 o C, RH= 85-90% the results showed that Java rambutan fruit which was packed in carton boxes combined PE bags then irradiated at 300 Gy dose could limit the browning pericarp, dehydration through the rate of browning, browning level and the percentage of weight loss. Irradiated ramtuban also remains their pulp quality when testing the soluble solids, the titratable acidity and the ascorbic acid content. Irradiation did not affect the cell structure of pericarp and pulp by investigating the total ion leakage. On the other hand, the topics also examined the influence of some postharvest handling and low-dose radiation on Java rambutan. The results showed that pre-irradiation processing: hot water treatment at 43 o C in 6 minute, dipping in cloruacalxi 0.4% + citric acid 0.5% solution in 3 minutes, packed in carton boxes + PE bags and irradiated at 300 Gy dose capable of maintaining the quality which extends the shelflife of Java rambutan more 4 days when kept under conditions of 13 o C, RH= 85-90%. (author)

Philippines' experience in marketing irradiated foods

International Nuclear Information System (INIS)

Lustre, A. O.; Ang, L.; Dianco, A.

1985-01-01

The Food Terminal Inc. in Manila, in cooperation with the Philippine Atomic Energy Agency and with funding support from the International Atomic Energy Agency in Vienna has been conducting storage and marketing studies on onions, garlic and mangoes. The objective is to gather loss reduction data and consumer reaction information that can serve as a basis for evaluating the risks and benefits involved in the establishment of a commercial food irradiator in the country. These studies show that irradiation reduces low-temperature storage losses in onions and garlic by 10-40% and post-storage marketing losses at ambient conditions by 16-50% in onions. Post-storage marketing trials not only indicate a significant reduction in losses during shipping and retail sale but a large increase in the marketability of irradiated commodities as measured by the rate of sale of the commodity and the price which it commands during the selling period. No adverse consumer reaction occurred during the sale of irradiated foods labelled as such except for a few comments indicating fear, ignorance and/or curiosity. The importance of irradiation as a substitute quarantine treatment for mangoes and for eliminating Salmonella in frozen foods for export is discussed in relation to the growing importance of these commodities to the Philippines' non-traditional export markets. Other applications of irradiation that could result in a perceptible improvement in the marketability of food commodities in the Philippines are discussed. Marketing studies are invaluable in evaluating the potential benefits of a new technology as food irradiation. In view of this, there is great interest in the completion of a pilot plant for food irradiation by the Philippine Atomic Energy Commission. The design and capacity of this plant are discussed

The effect of resveratrol in combination with irradiation and chemotherapy. Study using Merkel cell carcinoma cell lines

International Nuclear Information System (INIS)

Heiduschka, G.; Lill, C.; Brunner, M.; Thurnher, D.; Seemann, R.; Schmid, R.; Houben, R.; Bigenzahn, J.

2014-01-01

Merkel cell carcinoma (MCC) is a rare, but highly malignant tumor of the skin. In case of systemic disease, possible therapeutic options include irradiation or chemotherapy. The aim of this study was to evaluate whether the flavonoid resveratrol enhances the effect of radiotherapy or chemotherapy in MCC cell lines. The two MCC cell lines MCC13 and MCC26 were treated with increasing doses of resveratrol. Combination experiments were conducted with cisplatin and etoposide. Colony forming assays were performed after sequential irradiation with 1, 2, 3, 4, 6, and 8 Gy and apoptosis was assessed with flow cytometry. Expression of cancer drug targets was analyzed by real-time PCR array. Resveratrol is cytotoxic in MCC cell lines. Cell growth is inhibited by induction of apoptosis. The combination with cisplatin and etoposide resulted in a partially synergistic inhibition of cell proliferation. Resveratrol and irradiation led to a synergistic reduction in colony formation compared to irradiation alone. Evaluation of gene expression did not show significant difference between the cell lines. Due to its radiosensitizing effect, resveratrol seems to be a promising agent in combination with radiation therapy. The amount of chemosensitizing depends on the cell lines tested. (orig.) [de

Studies on mating competition of irradiated melon flies

International Nuclear Information System (INIS)

Limohpasmanee, W.

1994-01-01

Mating competition is the key factor for fruit flies control by using sterile insect technique project. Mass rearing and irradiation can reduce the mating competition of fruit flies. This experiment has purpose to evaluate the mating competition of the irradiated melon fly. The results show that mating competition values of irradiated melon flies were 0.36 and 0.24 when they mated with normal and irradiated females. Both normal male and female can mate more frequency than irradiated flies. (Z=1.322, P<0.05; Z=1.851, P<0.05). The results show that quality of mass rearing and irradiated melon fly was lower than the normal flies. So that quality of irradiated fly must be improved and the number of released flies as less must be higher than natural flies 6 time

Irradiation of chilled lamb

International Nuclear Information System (INIS)

Roberts, P.B.

1985-04-01

Chilled, vacuum-packed New Zealand lamb loins have been irradiated at doses between 1-8 kGy. The report outlines the methods used and provides dosimetry details. An appendix summarises the results of a taste trial conducted on the irradiated meat by the Meat Industry Research Institute of New Zealand. This showed that, even at 1 kGy, detectable flavours were induced by the radiation treatment

Study of growth mechanism of conducting polymers by pulse radiolysis

International Nuclear Information System (INIS)

Coletta, Cecilia

2016-01-01

Today conductive polymers have many applications in several devices. For these reasons they have received much attention in recent years. Despite intensive research, the mechanism of conducting polymers growth is still poorly understood and the methods of polymerization are limited to two principal ways: chemical and electrochemical synthesis. On the other hand, the complex properties of polymers can be controlled only if a good knowledge of polymerization process is acquired. In this case, it is possible to control the process during the synthesis (functionalization, hydrophilicity, chain length, doping level), and consequently to improve the conductive properties of the synthesized polymers. Water radiolysis represents an easy and efficient method of synthesis comparing to chemical and electrochemical polymerization routes. It enables the polymerization under soft conditions: ambient temperature and pressure, without any external dopant. Among all conductive polymers, poly(3, 4-ethylenedioxy-thiophene) (PEDOT, a derivative of poly-thiophene) and poly-Pyrrole (PPy) have gained some large scale applications for their chemical and physical proprieties. The aim of the present work was the synthesis of PEDOT and PPy in aqueous solution and the study of their growth mechanism by pulsed radiolysis. Thanks to the electron accelerator ELYSE, the use of pulsed radiolysis coupled with time-resolved absorption spectroscopy allowed to study the kinetics of polymerization. The first transient species involved in the mechanism were identified by time resolved spectroscopy and the rate constants were determined. First, the reaction of hydroxyl radicals onto EDOT and Py monomers was studied, as well as the corresponding radiation induced polymerization. Then, the study was transposed to others oxidizing radicals such as CO3 .- , N 3 . and SO 4 .- at different pHs. This approach allowed to check and to highlight the influence of oxidizing species onto the first transient species

Effect of gamma irradiation on nylon 6 films : swelling study

International Nuclear Information System (INIS)

Singh, L.P.; Chaudhuri, N.K.

1980-01-01

This paper reports on swelling studies of γ-irradiated nylon 6 films undertaken to investigate the effects of γ-irradiation in finer details. Benzyl alcohol has been used as the swelling agent. The kinetics of weight swelling of γ-irradiated nylon 6 films in benzyl alcohol was studied at different irradiation doses in the range 0 - 28.8 Mrad. It is observed that with increasing irradiation dose upto 14.4 Mrad the swelling, and hence the diffusion process are retarded; moreover, the sigmoidal nature of the percentage weight swelling vs (time)sup(1/2) plot is augmented. Above this critical dose the swelling and diffusion processes are accelerated. Besides, the sigmoidal behaviour recedes and is converted into linear behaviour at 28.8 Mrad. This behaviour indicates that a relaxation-controlled non-Fickian diffusion process is at work below 28.8 Mrad while at 28.8 Mrad a Fickian process is established. A significant effect on the equilibrium swelling in benzyl alcohol is observed. The plot of equilibrium weight swelling vs irradiation dose at 23deg C shows an initial decrease of swelling upto 3.6 Mrad at which swelling starts decreasing at accelerated rate in the dose range 3.6 - 7.6 Mrad. The rate slows down appreciably between 7.00 and 14.4 Mrad, above which there is a rapid fall. The results are correlated with scission and crosslinking processes through relative viscosity determination of formic acid solutions of the irradiated samples. It is established by combining viscosity data with kinetics and equilibrium swelling data that, besides scission, crosslinking processes are also at work in nylon 6 in the irradiation dose range 0 - 3.6 Mrad. It has been possible to bring out this point because the swelling technique seems to be preferentially sensitive towards crosslinking. (author)

Ion irradiation effects on tensile properties of carbon fibres

International Nuclear Information System (INIS)

Kurumada, A.; Ishihara, M.; Baba, S.; Aihara, J.

2004-01-01

Carbon/carbon composite materials have high thermal conductivity and excellent mechanical properties at high temperatures. They have been used as structural materials at high temperatures in fission and experimental fusion reactors. The changes in the microstructures and the mechanical properties due to irradiation damage must be measured for the safety design and the life assessment of the materials. The purpose of this study is to obtain a basic knowledge of the development of new carbon composite materials having high thermal conductivity and excellent resistance to irradiation damage. Five kinds of carbon fibres were selected, including a vapour growth carbon fibre (VGCF; K1100X), a polyacrylonitrile-based fibre (PAN; M55JB by Toray Corp.), two meso-phase pitch-based fibres (YS-15-60S and YS-70-60S by Nippon Graphite Fiber Corp.) and a pitch-based fibre (K13C2U by Mitsubishi Chemical Co.). They were irradiated by high-energy carbon, nickel and argon ions. Irradiation damages in the carbon fibres are expected to be uniform across the cross-section, as the diameters of the carbon fibres are about 20 μm and are sufficiently smaller than the ranges of ions. The cross-sectional areas increased due to ion irradiation, with the exception of the K1100X of VGCF. One of the reasons for the increases is the swelling of carbon basal planes due to lattice defects in the graphite interlayer. The tensile strengths and the Young's moduli decreased due to ion irradiation except for the K1100X of VGCF and the YS-15-60S of meso-phase pitch-based fibres. One of the reasons for the decreases is thought to be that the microstructures of carbon fibres are damaged in the axial direction, as ions were irradiated vertically with respect to the longitudinal direction of carbon fibres. The results of this study indicate that the VGCF and the meso-phase pitch-based carbon fibres could be useful as reinforcement fibres of new carbon composite materials having high thermal conductivity and

Experimental studies on prevention of trichinosis by food irradiation (Co60)

International Nuclear Information System (INIS)

Shimazu, Kimitaka

1993-01-01

A systemic study was performed to elucidate the effects of 60 Co irradiation on maturation or fecundity of Trichinella spiralis by assessing from parasitological, morphological and immunological points of view. Pieces of muscle tissue of mice infected with T. spiralis were irradiated with 60 Co at doses of 50, 75, 100, 150 and 200 Gy. These irradiated tissue (Experimental group) and non-irradiated tissues (Control group) were fed to healthy mice. Half of the mice were sacrificed 6 days after the ingestion. The number of adult worms were counted and subjected to statistical analysis, which disclosed a good correlation between the dose of 60 Co irradiation and worm damage; the higher the dose the more damage parasites had, and no adults were recovered if the tissue had been irradiated with more than 150 Gy prior to infection. The same tendency was true for the histopathology of the intenstines of host mice; the higher the dose the less tissue damage. Circulating antigens of T. spiralis and antibodies against T. spiralis were detected in every serum examined by ELISA. The remaining mice were sacrificed 30 days after the ingestion. The numbers of muscle larvae were counted and subjected to statistical analysis, which disclosed a good correlation between th dose of 60 Co irradiation and worm damage, and no larvae were recovered if the tissue had been irradiated with more than 75Gy. Higher concentrations of circulating antigens of T. spiralis and antibodies against T. spiralis were detected in the serum samples taken with muscle larvae. Thus this study established that 60 Co irradiation of more than 150 Gy caused complete damage on maturation, and that irradiation of more than 75 Gy caused complete damage on the fecundity of T. spimalis. (author)

Preliminary Studies for the Application of Irradiated-Food to Food Service Industry

Energy Technology Data Exchange (ETDEWEB)

Lee, Ju-Woon; Byun, Myung-Woo; Kim, Jae-Hun; Choi, Jong-Il; Song, Beom-Seok; Kim, Dong-Ho; Seo, Min-Won

2008-04-15

This study is to investigate ways to improve the marketability of irradiated food materials, through examining reports on toxicological safety and public acceptance of irradiated food materials. Many studies have reaffirmed the mutagenic, genotoxicological, microbiological, and nutritional safety of food irradiation, and consider it an important tool to reduce loss of food due to spoilage and pests. Although food irradiation could provide an opportunity to replace certain pesticides and food additives, there is ambivalence among consumers on whether or not the technology provides a real benefit. An easy and inexpensive tool to identify irradiation trace residue in foods, public trust building in industry through educating consumers with the benefit and uses of irradiation process are thought to be key elements for a successful market for irradiated food. Gamma irradiation at 50 kGy was applied to food materials for institutional food-service to evaluate their possible genotoxicity. The genotoxicity of 12 kinds of food materials irradiated at 50 kGy for institutional food-service was evaluated by Salmonella typhimurium reversion assay, chromosomal aberration test and in vivo micronucleus assay. The results of bacterial reversion assay with S. typhimurium TA98, TA100, TA1535 and TA1537 were negative in the 12 kinds of food materials irradiated at 50 kGy. No mutagenicity was detected in the assay with and without metabolic activation. In chromosomal aberration tests with CHL cells and in vivo mouse micronucleus assay, no significant difference in the incidences of chromosomal aberration and micronuclei was observed between non-irradiated and 50 kGy-irradiated food materials. These results indicate that food materials irradiated at 50 kGy for institutional food-service did not show any genotoxic effects under these experimental conditions.

Preliminary Studies for the Application of Irradiated-Food to Food Service Industry

International Nuclear Information System (INIS)

Lee, Ju-Woon; Byun, Myung-Woo; Kim, Jae-Hun; Choi, Jong-Il; Song, Beom-Seok; Kim, Dong-Ho; Seo, Min-Won

2008-04-01

This study is to investigate ways to improve the marketability of irradiated food materials, through examining reports on toxicological safety and public acceptance of irradiated food materials. Many studies have reaffirmed the mutagenic, genotoxicological, microbiological, and nutritional safety of food irradiation, and consider it an important tool to reduce loss of food due to spoilage and pests. Although food irradiation could provide an opportunity to replace certain pesticides and food additives, there is ambivalence among consumers on whether or not the technology provides a real benefit. An easy and inexpensive tool to identify irradiation trace residue in foods, public trust building in industry through educating consumers with the benefit and uses of irradiation process are thought to be key elements for a successful market for irradiated food. Gamma irradiation at 50 kGy was applied to food materials for institutional food-service to evaluate their possible genotoxicity. The genotoxicity of 12 kinds of food materials irradiated at 50 kGy for institutional food-service was evaluated by Salmonella typhimurium reversion assay, chromosomal aberration test and in vivo micronucleus assay. The results of bacterial reversion assay with S. typhimurium TA98, TA100, TA1535 and TA1537 were negative in the 12 kinds of food materials irradiated at 50 kGy. No mutagenicity was detected in the assay with and without metabolic activation. In chromosomal aberration tests with CHL cells and in vivo mouse micronucleus assay, no significant difference in the incidences of chromosomal aberration and micronuclei was observed between non-irradiated and 50 kGy-irradiated food materials. These results indicate that food materials irradiated at 50 kGy for institutional food-service did not show any genotoxic effects under these experimental conditions

The preliminary study on peculiar flavor from irradiated dried duck

Energy Technology Data Exchange (ETDEWEB)

Zongju, Li; Zongdao, Chen; Denyi, Xu [Southwest Agricultural Univ., Chongqing, SC (China)

1992-11-01

Peculiar flavor may be induced from irradiative preservation of meat with higher dose. The study on the irradiation of dried duck indicated that peculiar flavor is produced by a threshold of 1.5 kGy and intensifies with the increase of dose. The flavor primarily comes from muscle of dried duck especially from its water soluble protein. With the increase of dose, volatile carbonyl compounds, amines and sulfur compounds increased significantly. Paper chromatography analysis shows that two new volatile carbonyl compounds (R[sub f] =0.23 and 0.28) and a new volatile amine-propamine are induced by irradiation. This compounds may be the source of peculiar flavor in irradiated dried duck.

Wholesomeness study of irradiated salted and dried mackerel in rats

International Nuclear Information System (INIS)

Anukarahanonta, T.; Temcharoen, P.; Nagara, B.N.; Chudhabuddhi, C.; Bhamarapravati, N.

1981-01-01

A long-term multigeneration study was performed of the wholesomeness of irradiated salted and dried mackerel fed to the rats of Wistar strain and revealed no significant evidence that would impose a hazard attributable to irradiation with respect to the longevity, carcinogenecity, teratogenicity, dominant lethal, reproductive function and biophysiological function. Some abnormalities that were noted could be explained on the basis of differences in food quality due to the addition of fish protein and minerals rather than the irradiation effect

Study of the impact of food irradiation on preventing losses: Experience in Africa. Proceedings of a final research co-ordination meeting

International Nuclear Information System (INIS)

2002-05-01

There have been positive developments on food irradiation in different regions of the world, especially in the United States of America and several Asian and Latin American countries. In some countries in Africa, this technology has been studied in the past few decades with encouraging results. To assist these countries in conducting pilot scale research and development on irradiation of specific commodities of interest to them including market testing and feasibility to establish commercial irradiators for multi-purpose application, a Coordinated Research Project (CRP) on Impact of Irradiation to Prevent Food Losses in Africa was carried out between 1995 and 1999. This CRP demonstrated that food irradiation has a potential to reduce losses of basic staple food crops including yams, dried and smoked fish, potatoes and onions through pilot scale experiments carried out in some African countries. Small scale market testing of such irradiated food such as spices, potatoes and onions showed encouraging results. In some countries (Cote d'Ivoire, Egypt, Ghana, Senegal and South Africa), it is feasible to establish commercial irradiation facilities for treating food. In Morocco, irradiation shows a potential to meet quarantine requirements in international food trade. It should be noted that commercial scale application of irradiation of some food products has been carried out in South Africa since the 1980s

Study of the impact of food irradiation on preventing losses: Experience in Africa. Proceedings of a final research co-ordination meeting

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-05-01

There have been positive developments on food irradiation in different regions of the world, especially in the United States of America and several Asian and Latin American countries. In some countries in Africa, this technology has been studied in the past few decades with encouraging results. To assist these countries in conducting pilot scale research and development on irradiation of specific commodities of interest to them including market testing and feasibility to establish commercial irradiators for multi-purpose application, a Coordinated Research Project (CRP) on Impact of Irradiation to Prevent Food Losses in Africa was carried out between 1995 and 1999. This CRP demonstrated that food irradiation has a potential to reduce losses of basic staple food crops including yams, dried and smoked fish, potatoes and onions through pilot scale experiments carried out in some African countries. Small scale market testing of such irradiated food such as spices, potatoes and onions showed encouraging results. In some countries (Cote d'Ivoire, Egypt, Ghana, Senegal and South Africa), it is feasible to establish commercial irradiation facilities for treating food. In Morocco, irradiation shows a potential to meet quarantine requirements in international food trade. It should be noted that commercial scale application of irradiation of some food products has been carried out in South Africa since the 1980s.

Preliminary study of killing the larva of plodia interpunella by irradiation

International Nuclear Information System (INIS)

Wang Jide; Ma Xiaoping

1994-01-01

The results of killing the larva of plodia interpunella in the fruit by 60 Co γ-irradiation are described. The lowest effective dose for killing larva by irradiation is ca. 2000 Gy; the effective dose for immediately killing larva is 3000 Gy. The method is simple and easy and also suitable for the study of commercial irradiation of dry-fruit

Studies on the irradiated solids

International Nuclear Information System (INIS)

Lesueur, D.

1988-01-01

The 1988 progress report of the Irradiated Solids laboratory (Polytechnic School, France), is presented. The Laboratory activities concern the investigations on disordered solids (chemical or structural disorder). The disorder itself, its effects on the material physical properties and the particle-matter interactions, are investigated. The research works are performed in the following fields: solid state physics, irradiation and stoechiometric defects, and nuclear materials. The scientific reviews, the congress communications and the thesis are listed [fr

Thermal studies on unirradiated and γ-irradiated polymer of allyl diglycol carbonate

International Nuclear Information System (INIS)

Kalsi, P.C.; Pandey, A.K.; Iyer, R.H.; Singh Mudher, K.D.

1995-01-01

The thermal decomposition of unirradiated and γ-irradiated (5.93-15.5 MRad dose range) allyl diglycol carbonate polymer (trade name, CR-39) was studied by thermogravimetry (TG) and differential thermal analysis (DTA). These studies indicate four main decomposition steps in CR-39 polymer in air. Assessment of the influence of radiation dose on the above range shows that while the 5.93 MRad γ-irradiated polymer CR-39 degrades in three steps, the 15.5 MRad γ-irradiated polymer degrades in only two steps. The kinetics of the different stages of degradation were also evaluated from the TG curves. Irradiation enhances the decomposition rate and the effect increases further with increasing radiation dose. The activation energy values calculated for all the decomposition stages decrease on irradiation

Study of gamma irradiation effect on commercial TiO2 photocatalyst

International Nuclear Information System (INIS)

Bello Lamo, M.P.; Williams, P.; Reece, P.; Lumpkin, G.R.; Sheppard, L.R.

2014-01-01

The aim of this work is to understand the effect of gamma irradiation on commercial TiO 2 photocatalyst for water treatment applications. Previous studies concluded that gamma-irradiation is able to modify the electronic properties of TiO 2 based photocatalysts and consequently their photocatalytic performance. However, there are some discrepancies in the literature where on one hand a significant enhancement of the material properties is reported and on the other hand only a weak effect is observed. In this study a surface effect on TiO 2 is confirmed by using low and medium gamma irradiation doses. - Highlights: • Gamma irradiated TiO 2 is investigated for photocatalytic water treatment. • By low gamma doses, no change in surface properties is observed. • However, a surface defect is found for gamma irradiated TiO 2 at higher doses. • XPS measurements showed an increase of hydroxyl groups. • That may cause a variation of its adsorption capacity

Multigeneration feeding studies with an irradiated whole diet

International Nuclear Information System (INIS)

Aravindakshan, M.; Chaubey, R.C.; Chauhan, P.S.; Sundaram, K.

1978-01-01

Multigeneration feeding studies have been carried out to investigate the effects of long-term feeding of an irradiated whole diet in Wistar rats. The parent and the four successive generations were fed on a nutritionally adequate test diet exposed to either 0.2 or 2.5Mrad gamma radiation and the effects, if any, on various parameters of animal health were assessed. In addition to an unirradiated test control, a historical control group fed on stock laboratory rations was also employed for comparison. The test diet consisted of various components including some of the basic ingredients of human diet in India. Exposure of the test diet to 0.2 or 2.5Mrad did not affect the food efficiency ratio and there were no significant differences in the growth rates of animals fed on unirradiated or irradiated diets. Reproductive performance of the rats fed on irradiated or unirradiated diets belonging to the parent, first, second or third generations were also comparable. Mortality rates and reproductive function in relation to age were also not altered due to feeding of irradiated whole diets. The haematological profile and the serum enzymes of the animals of all the generations fed irradiated diets were within normal limits. Though some differences were observed in the relative weights of some organs, these effects were limited to a particular generation, did not show any definite pattern and could not be related to the ingestion of irradiated diets. First-generation rats examined at 100-104 weeks for gross pathological manifestations including tumour incidence also did not indicate any significant differences among groups. (author)

Effect of dose on radiation-induced conductivity in polymers

International Nuclear Information System (INIS)

Tyutnev, A.P.; Saenko, V.S.; Pozhidaev, E.D.; Ikhsanov, R.Sh.

2007-01-01

Numerical simulation of radiation-induced conductivity in polymers upon long-term irradiation on the basis of the generalized Rose-Fowler-Vaisberg model, which allows for both dipolar carrier transport and generation of radiation traps during irradiation, was performed. The unusual properties of radiation-induced conductivity, such as the appearance of a maximum on current transients, the absence of a steady state, and a substantial difference between these curves for the first and subsequent irradiation, are rationalized in terms of the formation of free radicals, the major feature of radiolysis in the chemical aspect. This interpretation does not require the involvement of degradation or crosslinking processes, unlike other interpretations that appear in the literature. With the use of low-density polyethylene as an example, it was shown that radiation-induced conductivity both upon pulse and continuous irradiation can satisfactorily be described with the unified set of parameters of the generalized Rose-Fowler-Vaisberg model [ru

Positron annihilation and Moessbauer studies of neutron irradiated reactor pressure vessel steels

International Nuclear Information System (INIS)

Brauer, G.; Matz, W.; Liszkay, L.; Molnar, B.

1990-11-01

Positron annihilation (lifetime, Doppler broadening) and Moessbauer studies on unirradiated, neutron irradiated and neutron irradiated plus annealed reactor pressure vessel steels (Soviet type 15Kh2NMFA) are presented. The role of microstructural properties and the formation of irradiation-induced precipitates is discussed. (orig.) [de

Comparative study of thermoluminescence detection methods for irradiated spices

International Nuclear Information System (INIS)

Kawamura, Y.; Kojima, K.; Sugita, T.; Yamada, T.; Saito, Y.

1995-01-01

The thermoluminescence (TL) detection methods for irradiated spices were compared using spice samples obtained on the Japanese market, irradiated at doses of 1, 5, 10 and 30 kGy and stored for 1 year before analysis. The TL intensities of irradiated spices were stable for 1 year after irradiation. Measurement with whole samples failed to identify irradiated samples. Minerals were separated from spices in sodium tungstate saturated solution and/or sodium polytungstate solution. The TL intensity of minerals which had undergone irradiation was significantly increased for all samples. However, the ranges of TL intensity of irradiated and unirradiated samples overlapped. Clear discrimination has been obtained between the TL ratios of irradiated and unirradiated spices by using normalized measurement with reirradiation. The detection limit in terms of irradiation dose is 1 kGy even in a sample that has been irradiated 1 year prior to analysis. Normalization is the best technique currently available for thermoluminescence analysis to identify irradiated spices

Study on the irradiation decontamination of traditional Chinese medicines

International Nuclear Information System (INIS)

Wang, B.; Shi, S.; Li, B.; Wang, G.

2005-01-01

Traditional Chinese Medicines (TCMs) are natural products prepared from plants, minerals and animals, it is easy for contamination by microorganisms to occur; thus causing problems in complying with the requirements laid down for passing microbial limit tests. We selected some kinds of TCMs, including unprocessed materia medica, traditional Chinese patent medicine (TCPMs) and chemical constituents for irradiation by 60 Co gamma ray and investigating the results in terms of microbiology, chemistry, pharmacology and toxicology. We found no evidence of changes in most of the tested items, which indicates that the irradiation method could be employed for decontamination of TCMs. However, some chemical constituents of unprocessed materia medica, such as gentiopicrin in Radix Gentianae Macrophyllae and 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside in Radix Polygoni Multiflori, decomposed when these crude materials were irradiated with dose of 5kGy. Further study revealed that although the medicinal were altered by irradiation, the monomers of some of these chemical constituents were not affected. In addition to investigation of the items described above, the doses of irradiation were selected experimentally to ensure that, after irradiation, the TCMs passed the microbial limit tests described in the Chinese Pharmacopoeia. The lowest possible doses were used in order to avoid any impairment of the quality and clinical efficacy of the effective ingredients of the TCMs. (author)

Fundamental irradiation studies on vanadium alloys

International Nuclear Information System (INIS)

Loomis, B.A.; Garner, F.A.; Ermi, A.M.

1985-05-01

A joint experiment on the irradiation response of simple vanadium alloys has been initiated under the auspices of the DAFS and BES progams. Specimen fabrication is nearly complete and the alloys are expected to be irradiated in lithium in FFTF-MOTA Cycles 7 and 8

Patterning and Conductivity Modulation of Conductive Polymers by UV Light Exposure

DEFF Research Database (Denmark)

Edberg, Jesper; Iandolo, Donata; Brooke, Robert

2016-01-01

to control the conductivity in the conjugated polymer poly(3,4-ethylenedioxythiophene):tosylate by more than six orders of magnitude in addition to producing high-resolution patterns and optical gradients. The mechanism behind the modulation in the polymerization kinetics by UV light irradiation as well...

Studies on combination effects of peplomycin and x-ray irradiation

International Nuclear Information System (INIS)

Munenaga, Yasuichi

1984-01-01

In order to study effects and methods of combination of peplomycin (PEP) and x-ray irradiation, inhibitory effects on DNA synthesis were investigated with synchronized cells from the parotid gland of mice treated with isoproterenol (IPR) and inhibitory effects on cell proliferation were investigated with Ehrlich solid tumor cells. PEP had dose-dependent effects on the inhibition of DNA synthesis and on the prolongation of cell cycles in the IPR-treated mouse cells. When 3.0 and 5.0 mg/kg of PEP were combined with 200 rad of x-ray irradiation at the early phase of G 1 , synergistic effects on the inhibition of DNA synthesis were seen. This was most noted in the group with PEP 30 minutes before irradiation. PEP had also dose-dependent inhibitory effects on the proliferation of Ehrlich solid tumor cells. This was increased when x-ray irradiation was combined with PEP. Inhibitory effects on the proliferation of tumor cells were greater when PEP was given before x-ray irradiation than after x-ray irradiation, regardless of the amount. The greatest effect was seen in the group with PEP 30 minutes before irradiation, as well as in the experiment with IPR-treated mouse cells. (Namekawa, K.)

PIE on Safety-Tested Loose Particles from Irradiated Compact 4-4-2

Energy Technology Data Exchange (ETDEWEB)

Hunn, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gerczak, Tyler J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Morris, Robert Noel [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baldwin, Charles A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Montgomery, Fred C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-04-01

Post-irradiation examination (PIE) is being performed in support of tristructural isotropic (TRISO) coated particle fuel development and qualification for High Temperature Gas-cooled Reactors (HTGRs). This work is sponsored by the Department of Energy Office of Nuclear Energy (DOE-NE) through the Advanced Reactor Technologies (ART) Office under the Advanced Gas Reactor Fuel Development and Qualification (AGR) Program. The AGR-1 experiment was the first in a series of TRISO fuel irradiation tests initiated in 2006. The AGR-1 TRISO particles and fuel compacts were fabricated at Oak Ridge National Laboratory (ORNL) in 2006 using laboratory-scale equipment and irradiated for 3 years in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL) to demonstrate and evaluate fuel performance under HTGR irradiation conditions. Post-irradiation examination was performed at INL and ORNL to study how the fuel behaved during irradiation, and to test fuel performance during exposure to elevated temperatures at or above temperatures that could occur during a depressurized conduction cooldown event. This report summarizes safety testing and post-safety testing PIE conducted at ORNL on loose particles extracted from irradiated AGR-1 Compact 4-4-2.

Study on detection of electron beam irradiated food by ESR spectroscopy and comparison of the ESR spectrum of electron beams and γ-rays

International Nuclear Information System (INIS)

Li Weiming; Ha Yiming; Wang Feng

2012-01-01

The study was conducted to detect electron beam irradiated food by ESR spectroscopy. The white pepper powder, paprika powder, cumin powder and pistachios were used as test materials to study the feature changes of ESR spectrum and the relationship between ESR intensity and irradiation dose in different doses, the shape variation of ESR spectrum in γ-rays and electron beams in the same sample was also compared. The results showed that the ESR spectrum of 4 kinds of irradiated samples was obviously different before and after irradiation, the intensity of ESR signal increased with the increasing of the absorbed dose. The dose above 432 Gy could be detected in white pepper powder and pistachios, the dose above 875 Gy could be detected in paprika powder and cumin powder. The ESR intensity of all samples decreased during the storage time (200 d), even after 200 days the ESR method could also be used to detect whether or not the samples have been irradiated. The same dosage of y-rays and electron beams has no significant influence on the shape of ESR spectrum, however, the difference of irradiation mechanism caused slight impact on ESR intensity. The results could provide the technical basis for the application of ESR method in detecting electron beam irradiated food. (authors)

Study on detection of electron beam irradiated food by ESR spectroscopy and comparison of the ESR spectrum of electron beams and γ-rays

International Nuclear Information System (INIS)

Li Weiming; Ha Yiming; Wang Feng

2011-01-01

The study was conducted to detect electron beam irradiated food by ESR spectroscopy. The white pepper powder, paprika powder, cumin powder and pistachios were used as test materials to study the feature changes of ESR spectrum and the relationship between ESR intensity and irradiation dose in different doses, the shape variation of ESR spectrum in γ-rays and electron beams in the same sample was also compared. The results showed that the ESR spectrum of 4 kinds of irradiated samples was obviously different before and after irradiation, the intensity of ESR signal increased with the increasing of the absorbed dose. The dose above 432 Gy could be detected in white pepper powder and pistachios, the dose above 875 Gy could be detected in paprika powder and cumin powder. The ESR intensity of all samples decreased during the storage time (200 d), even after 200 days the ESR method could also be used to detect whether or not the samples have been irradiated. The same dosage of γ-rays and electron beams has no significant influence on the shape of ESR spectrum, however, the difference of irradiation mechanism caused slight impact on ESR intensity. The results could provide the technical basis for the application of ESR method in detecting electron beam irradiated food. (authors)

Electron beam irradiation: laboratory and field studies of cowpea seeds

International Nuclear Information System (INIS)

Srinivasan, K.; Chauhan, S.K.; Prasad, T.V.; Pramod, R.; Verma, V.P.; Petwal, V.; Dwivedi, J.; Bhalla, S.

2015-01-01

Cowpea (Vigna unguiculata) rich in protein and vitamins is emerging as one of the most important food legumes to tackle malnutrition. Pulse beetles (Callosobruchus chinensis and C. maculatus) are the pests of economic importance causing enormous losses during storage. Although various pest management strategies exist for the control of these pests, environmental concerns necessitate developing ecofriendly strategies. Electron beam (EB) irradiation has the potential to be a viable, non-chemical, residue-free strategy for management of pulse beetles during storage, but higher doses affect seed germination and viability. Hence, the present investigation was taken up to analyse the dosage effect of the irradiation on seed attributes of cowpea. Healthy cowpea seeds were irradiated with low energy electrons at different doses viz., 180, 360, 540, 720, 900, 1080, 1260, 1440 and 1620 Gy at 500 keV using the EB Accelerator facility at Raja Ramanna Centre for Advanced Technology, Indore. EB irradiated seeds were tested for physiological viz., germination, seedling vigour and vigour index and biochemical parameters viz., electrical conductivity of seed leachate, seed viability/tetrazolium test and dehydrogenase activity. Germination and vigour of the irradiated seeds were evaluated as per the ISTA Rules (ISTA, 1996). Vigour index was calculated as the product of germination percentage and seedling vigour. About 3,000 irradiated seeds from each dose were grown in the field at the Experimental farm, National Bureau of Plant Genetic Resources, New Delhi. Seeds harvested from 1500 individual plants of M 1 generation from each dose (50 seeds from each plant individually) were sown in next season and observed for chlorophyll mutations, if any. Results revealed that doses upto 1080 Gy (88%) did not affect the germination of cowpea seeds drastically as compared to untreated seeds (98%). Lower doses viz., 180 and 360 Gy had no impact on vigour components while higher doses (1080 Gy

Renal effects of renal x irradiation and induced autoallergic glomerulonephritis

International Nuclear Information System (INIS)

Rappaport, D.S.

1977-01-01

This study was conducted to determine what, if any, influence a single large x-ray exposure of kidney has on the development and course of an experimental autoallergic glomerulonephritis (EAG) in rats. The EAG was induced by immunization with B. pertussis vaccine and homogenate of homologous kidney tissue and Freund's complete adjuvant. Rats were either immunized, sham-immunized, irradiated (1500 R to right kidney temporarily exteriorized), sham-irradiated, or both immunized and irradiated. Immunized-irradiated animals were irradiated either 4 or 2 weeks prior to, concurrently with, or 1 or 2 weeks after immunization, and were sacrificed at 2, 4, 6, 10, or 14 weeks post-immunization. Immunized-only and sham-immunized-only animals were sacrificed at corresponding post-immunization times, and irradiated-only and sham-irradiated-only animals were sacrificed at corresponding post-irradiation times. Progressive arteriolonephrosclerosis (ANA) was observed in right (irradiated) kidneys following x irradiation. The experimental autoallergic glomerulonephritis (EAG) was observed in both kidneys following immunization. The histopathological changes associated with EAG were distinct from those associated with ANS

Biophysical studies of irradiated thymocytes. 1. Surface changes

Energy Technology Data Exchange (ETDEWEB)

Sungurov, A Yu; Tokalov, S V; Petrov, Yu P; Sharlaeva, T M

1985-08-15

In order to study postirradiation changes in thymus lymphocyte surface, a number of biophysical analytical methods was used: the cell two-partition method, the physical adhesion method, fluorescence intensity and binding parameters of negatively charged ANS probe. Reduction of cell distribution factor in two-phase system and adhesion of thymocytes to cotton 1 hour after irradiation, as well as abrupt change in parameters of binding the probe in the interval of 3-4 hours after X-ray irradiation at the dose of 4 Gy are demonstrated.

Food irradiation: Public opinion surveys

International Nuclear Information System (INIS)

Kerr, S.D.

1987-01-01

The Canadian government are discussing the legislation, regulations and practical protocol necessary for the commercialization of food irradiation. Food industry marketing, public relations and media expertise will be needed to successfully introduce this new processing choice to retailers and consumers. Consumer research to date including consumer opinion studies and market trials conducted in the Netherlands, United States, South Africa and Canada will be explored for signposts to successful approaches to the introduction of irradiated foods to retailers and consumers. Research has indicated that the terms used to describe irradiation and information designed to reduce consumer fears will be important marketing tools. Marketers will be challenged to promote old foods, which look the same to consumers, in a new light. Simple like or dislike or intention to buy surveys will not be effective tools. Consumer fears must be identified and effectively handled to support a receptive climate for irradiated food products. A cooperative government, industry, health professional, consumer association and retailer effort will be necessary for the successful introduction of irradiated foods into the marketplace. Grocery Products Manufacturers of Canada is a national trade association of more than 150 major companies engaged in the manufacture of food, non-alcoholic beverages and array of other national-brand consumer items sold through retail outlets

Structure changes of irradiated UO2

International Nuclear Information System (INIS)

Komatsu, Junji; Yokouchi, Yoji; Kajiyama, Takashi; Terunuma, Toshihiro; Koizumi, Masumichi

1973-01-01

The structural change of UO 2 irradiated in GETR reactor was analyzed on void distribution, fuel cracking, and gap conductance between fuel and cladding. Metallographic analysis was carried out on 21 sections of irradiated fuel pins. Radial void distribution was measured by the linear analysis technique based on the equivalence between the volume fraction of voids and the intercepted length of lines between void boundaries. Fuel cracks were classified into two types, namely radial cracks and circumferential cracks. The radial position, length, angle and number of each fuel clad were measured on metallographic section and autoradiography. The gap conductance between fuel and cladding was calculated from the equation h = q/(T sub(s) - T sub(i)) where h is gap conductance, T sub(i) is inside clad temperature and T sub(s) is outside clad temperature. In void distribution, as the result of studying the effect of linear heat rating on the radial void fraction of UO 2 fuel irradiated with the similar level of burnup, one specimen showed that the void fraction of columnar grain growth region was comparable to that of fabricated region, and two specimens showed higher void fraction at fabricated region than the calculated one. In fuel cladding, no significant effect of burnup on fuel cracking was observed, and the number of fuel cracking increased with shutdown or scram numbers, but the radial position of circumferential cracks was not much changed. In gap conductance, it was influenced by the estimation of temperature of columnar grain growth. (Iwakiri, K.)

Irradiation effects on fuels for space reactors

International Nuclear Information System (INIS)

Ranken, W.A.; Cronenberg, A.W.

1984-01-01

A review of irradiation-induced swelling and gas release experience is presented here for the three principal fuels UO 2 , UC, and UN. The primary advantage of UC and UN over UO 2 is higher thermal conductivity and attendant lower fuel temperature at equivalent pellet diameter and power density, while UO 2 offers the distinct benefit of well-known irradiation performance. Irradiation test results indicate that at equivalent burnup, temperature, and porosity conditions, UC experiences higher swelling than UO 2 or UN. Fission gas swelling becomes important at fuel temperatures above 1320 K for UC, and at somewhat higher temperatures for UO 2 and UN. Evidence exists that at equivalent fuel temperatures and burnups, high density UO 2 and UN experience comparable swelling behavior; however, differences in thermal conductivity influence overall irradiation performance. The low conductivity of UO 2 results in higher thermal gradients which contribute to fuel microcracking and gas release. As a result UO 2 exhibits higher fractional gas release than UN, at least or burnups up to about 3%

About the study of irradiation effects on in-core instrumentation

International Nuclear Information System (INIS)

Angelino, G.

1972-01-01

The knowledge of in-core instrumentation performances is a very important item when irradiations of technological interest are concerned. When measurement of small changes in mechanical or thermal properties is of major importance, the effect of neutron and gamma irradiation on various transducers must be thoroughly evaluated. A rig mock-up was irradiated in the Triga Mark II Reactor of the Pavia University to assess the possibility of carrying out a study on irradiation effects on in-core instrumentation. Data on neutron flux distribution and γ-heating effect were collected from this preliminary experiment; at the same time a complete check was performed on rig assembling procedure, on the behaviour under operating conditions, and on the reactor loading and unloading operations. (author)

Irradiation of carbon nanotubes with carbon projectiles: A molecular dynamics study

Energy Technology Data Exchange (ETDEWEB)

Denton, Cristian D. [Departamento de Fisica Aplicada, Universidad de Alicante, 03080 Alicante (Spain); Heredia-Avalos, Santiago; Moreno-Marin, Juan Carlos [Departamento de Fisica, Ingenieria de Sistemas y Teoria de la Senal, Universidad de Alicante, 03080 Alicante (Spain)

2013-04-15

The irradiation of carbon based nanostructures with ions and electrons has been shown to be an appropriate tool to tailor their properties. The defects induced in the nanostructures during irradiation are able to modify their mechanical and electronic properties. Here we simulate the irradiation of carbon nanotubes with carbon ions using a molecular dynamics code. We use the Tersoff potential joined smoothly to the Universal Ziegler-Biersack-Littmark potential at short distances. We study the number of defects produced after irradiation with a single carbon ion finding a saturation with its energy at {proportional_to} 3 keV. We observe, after continuum irradiation with low energy ions, the formation of bumps in the irradiated region. For larger energy ions we find that the diameter of the nanotube shrinks as shown in previous works. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Effects of gamma irradiation, modified atmosphere packaging and delay of irradiation on quality of fresh-cut iceberg letuce

Science.gov (United States)

The study was conducted to investigate the effect of modified atmosphere packaging (MAP) and delay of irradiation application on the quality of cut Iceberg lettuce. Overall visual quality and tissue browning of cut lettuce were evaluated using a scale of 9-1 while texture was analyzed instrumentally...

Monte Carlo studies of the Portuguese gamma irradiation facility. The irradiator geometry and its influence on process parameters

International Nuclear Information System (INIS)

Oliveira, C.; Ferreira, L.; Salgado, J.

2001-01-01

The paper describes a Monte Carlo study of dose distributions, minimum dose and uniformity ratio for the Portuguese Gamma Irradiation Facility. These process parameters are calculated using the MCNP code for several irradiator geometries. The comparison of the simulated results with the experimental results carried out using Amber Perspex dosimeters in a routine process of the gamma facility for a given material composition and density reveals good agreement. The results already obtained allow to conclude that the dose uniformity is not very sensitive to the irradiator geometry for density value ρ = 0.1 and for a dynamic process. (orig.)

Pilotscale studies of dried fish irradiation. Part of a coordinated programme in Asian Regional Cooperative Project on Food Irradiation

International Nuclear Information System (INIS)

Maha, M.

1983-03-01

Pilot scale experiments on irradiation of semi-dried mackerel with regard to shelf-life extension, packaging, transportation and cost-analysis were carried out. The results showed that dipping mackerel in saturated brine for 5 hours and then soaking it in 2% potassium sorbate before sun-drying to approximately 40% moisture content produced a good quality product. Sorbate treatment was effective in controlling mould growth while irradiation with 2 kGy was effective in reducing the bacterial load. Carton boxes were found most suitable as packaging material for irradiated dried fish from the point of view of strength, convenience for irradiation and better dose uniformity ratio than polypropylene bags which have ununiform configuration. Irradiation with doses up to 10 kGy has no significant effect on physical properties of the packaging materials tested. Carton boxes of 20 kg capacity provided with strapping bands are durable for land or sea transportation of dried fish. A radiation dose of 0.5 kGy was sufficient to control insect damage and reduce mould growth on dried fish. Irradiated dried fish can be marketed for 3-4 months at ambient conditions in Jakarta. Small scale consumer studies of irradiated samples using employees of the institute showed no negative reactions. Using the small pilot irradiator at CAIR and assuming 1 kGy minimum dose for dried fish, the total cost of irradiation and packaging was estimated to be approximately 10 U.S. cents/kg of fish, which is about 2-3% of the cost of the product

Experience with a pilot plant for the irradiation of sewage sludge: Bacteriological and parasitological studies after irradiation

International Nuclear Information System (INIS)

Wizigmann, I.; Wuersching, F.

1975-01-01

Comparative bacteriological studies of sewage sludge in a sewage plant have demonstrated that mechanical-biological sewage treatment reduced the total bacterial count and those of Enterococces by 2 log and the Enterobacteriaceae by 3-4 log. Frequently Salmonella could be isolated from sewage sludge. A further reduction of viable micro-organisms could be achieved by irradiation of sewage sludge ( 60 Co, gamma-radiation, 260 krad, 210 min). This reduction amounted to an average of 2 log with Enterococces and total bacterial count, and to 5 log with Enterobacteriaceae. Out of 40 samples investigated after irradiation, two contained Salmonella. The hygienic effects of the irradiation unit were demonstrated by means of a model experiment with bacterial pure cultures. Micro-organisms of different species as well as strains of the same species differ in their sensitivity to irradiation. Parasitological experiments with eggs of Ascaris suum were carried out to test the inhibitory or killing ability of the gamma rays on the developing stages of parasites

Utilization of irradiated sludge for fish feed

International Nuclear Information System (INIS)

Harsojo; Syamsu, Suwirma; Subagyo, Lydia Andini

1994-01-01

An experiment was conducted to study the use of irradiated sludge pellet for fish feed, namely pellet A consisting of irradiated sludge and shrimp waste (1:3); pellet B consisting of irradiated sludge and commercial pellet (1:2). Pellet C, which is a commercial fish feed, was used as control. Catfish (Clarias gariepinus) was used in this experiment. The feed pellet with a dose of 5% of total body weight was given 3 times per day. The results of the experiments showed that based on food conversion for the relative growth of the catfishes, and heavy metal content, pellet A was the best. No contamination of Salmonella or Shigella bacteria was detected in each pellet. (author). 8 refs, 3 tabs, 1 fig

Transportation and storage studies on irradiated Alphonso mangoes

International Nuclear Information System (INIS)

Farkas, J.; Dharkar, S.D.; Sreenivasan, A.

1972-01-01

Control as well as skin coated (6% ''Myvacet'') and/or irradiated (25 to 35 krad) mangoes were packed in baskets in dry paddy straw and shipped by rail. After a storage at a temperature of 25 to 32 0 C for a period of 8 days, the baskets were shipped back. After receipt in the laboratory the fruits were kept under observation for 5 more days and then scored for ripening and marketability as assessed by appearance, skin gloss and typical flavour. 100 per cent of fruits skin-coated and irradiated were marketable at the end of the experiment. None of the unirradiated control fruits were saleable by this time, while 66%, of the irradiated fruits were in acceptable condition. In further experiments one dozen mangoes each from control, irradiated and skin-coated and irradiated groups were wrapped individually in tissue paper and packed tightly in a plyweed box. This consignment was air-lifted from Bombay to Budapest, a distance of about 5600 kilometers. The time interval between irradiation and their receipt in Hungary was 4 days. The mangoes were assessed for their storage characteristics by various parameters that included physiological loss in weight, puncture resistance of the skin, pulp texture, carotenoids, acidity and organoleptic attributes, at various periods during storage. It was found that ripening and senescence are strikingly delayed in mangoes by skin-coating and radiation treatment. The treated mangoes retained their skin-resistance while the disappearance of chlorophyl and formation of carotenoids were substantially delayed. Weight loss in storage was lower and reduction of acidity and formation of sugars in the fruit flesh took place later. Organoleptically, the fruits subjected to the combination treatment were good. These studies point to the feasibility of the combination treatment in prolonging the shelf life of fruits significantly to enable their transport to distant countries. (F.G.)

A study on the irradiation effect of reactor materials using a cyclotron

Energy Technology Data Exchange (ETDEWEB)

Hong, Joon Hwa; Ji, Se Hwan; Kang, Yung Hwan; Park, Duk Keun; Park, Jong Man; Lee, Bong Sang; Oh, Jong Myung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1994-12-01

The objectives of the present study are to develop the simulation techniques of neutron irradiation through ion irradiation using a Cyclotron and small specimen techniques and to evaluate radiation effects of reactor materials. Effects of proton or neutron irradiation on domestic 12Cr-1MoV and SA508-3 steels were evaluated by small scale specimen test techniques, i.e, small punch and miniaturized tensile test. In order to study the radiation damage mechanism, irradiation effects of the steels were investigated by means of property change tests such as microstructure, physical and thermal properties. Feasibility study on application of a magnetic non-destructive methods to evaluate radiation effects on RPV materials was performed. 109 figs, 12 tabs, 102 refs. (Author).

A study on the irradiation effect of reactor materials using a cyclotron

International Nuclear Information System (INIS)

Hong, Joon Hwa; Ji, Se Hwan; Kang, Yung Hwan; Park, Duk Keun; Park, Jong Man; Lee, Bong Sang; Oh, Jong Myung

1994-12-01

The objectives of the present study are to develop the simulation techniques of neutron irradiation through ion irradiation using a Cyclotron and small specimen techniques and to evaluate radiation effects of reactor materials. Effects of proton or neutron irradiation on domestic 12Cr-1MoV and SA508-3 steels were evaluated by small scale specimen test techniques, i.e, small punch and miniaturized tensile test. In order to study the radiation damage mechanism, irradiation effects of the steels were investigated by means of property change tests such as microstructure, physical and thermal properties. Feasibility study on application of a magnetic non-destructive methods to evaluate radiation effects on RPV materials was performed. 109 figs, 12 tabs, 102 refs. (Author)